The main malfunctions of the power system are the interruption of the fuel supply to the carburetor, the formation of a too lean or rich combustible mixture, fuel leakage, difficult starting of a hot or cold engine, unstable engine idling, interruptions in engine operation in all modes, as well as increased consumption fuel.

Determination of clogging of the fuel supply line from the gas tank is carried out by purging it with a tire pump with a special cone nozzle or using a compressor. To do this, disconnect from fuel pump fuel supply hose to it, insert a cone nozzle into it and supply air into it using a pump or compressor. In this case, the air should easily exit into the fuel tank (gurgling sounds will be heard in the tank). In case of poor air permeability through the fuel line or its absence, you can try to blow it out by increasing the pressure of the supplied air. If it is not possible to eliminate the malfunction by purging, then you should remove and clean the fuel inlet pipe of the gas tank with a strainer or replace the clogged or dented fuel line from the gas tank, and also remove and thoroughly rinse the gas tank with hot water to remove any contaminants in it. If there are no blockages in the fuel supply line to the fuel pump, they proceed to troubleshooting the fuel pump.

Troubleshooting the fuel pump should begin with a thorough inspection in order to detect fuel leakage through leaky connections of its parts or damaged diaphragms. When fuel is pumped through the connections of the pump parts, it is necessary to tighten their fastenings. You should also remove the pump cover, check and clean it strainer and test the pump again.

If the pump diaphragms are damaged, fuel will leak through a special hole in the lower part of the housing, and also enter the engine crankcase, therefore, with this malfunction, increased fuel consumption, an increase in the oil level in the engine and a drop in its pressure due to gasoline ingress. At the same time, diluted oil flows easily from the dipstick and smells like gasoline. These indirect signs also make it possible to detect minor damage to the fuel pump diaphragms in operation, in which the fuel pump still retains sufficient performance to provide sufficient fuel supply for engine operation. Damaged diaphragms are replaced. If, after checking and replacing the diaphragms, the fuel supply to the pump is not restored, then it must be removed from the vehicle for repair or replacement with a new one.

If the fuel pump is in good condition and provides sufficient fuel pressure, then you should check if the carburetor strainer is clogged. To do this, unscrew the plug of the strainer, clean it and blow compressed air.

The formation of a too lean combustible mixture is accompanied by "shots" from the carburetor, overheating of the engine, loss of its power (poorly "pulls"); it should be borne in mind that the same symptoms are characterized by the operation of the engine with too early and too late ignition. Therefore, before looking for a malfunction in the power system, it is necessary to check the ignition timing setting.

To eliminate the malfunction in each specific case, it is necessary to accurately determine its cause.

It is necessary to determine and eliminate the listed malfunctions in the following order: check the fuel supply using the methods indicated above; with normal fuel supply, check for air leaks in the connections. To do this, with the engine running, close the air damper and turn off the ignition, then inspect the junction of the carburetor and the intake manifold. The appearance of wet spots of fuel indicates the presence of leaks in these places. To eliminate the malfunction, it is necessary to tighten the nuts and bolts of the fastening. If no air leakage is detected, check the fuel level in float chamber and adjust it if necessary.

Clogged jets are blown out with compressed air from a compressor or a conventional tire pump with a cone nozzle (with the carburetor cover removed). If it is impossible to blow through the jet, it is allowed to clean it with soft copper wire.

The formation of a too rich combustible mixture is accompanied by the following symptoms: black smoke and “shots” from the muffler, loss of engine power and overheating, excessive fuel consumption, gasoline getting into the oil, carbon deposits in the combustion chambers and on the pistons.

These faults are identified and corrected in the following order:

Remove the carburetor cover and check the float mechanism, if necessary, eliminate the identified malfunctions and adjust the fuel level in the float chamber.

Difficulty starting a hot engine may be due to incomplete opening air damper carburetor, increased level of gasoline in the float chamber (overflow), as well as violations of adjustment and clogging of the jet of the system idle move. To fix the problem, you can first try to start the engine by depressing the throttle control pedal all the way (purge start). If this does not help, you should check and, if necessary, adjust the length of the air damper cable, ensuring its full opening and closing, check and adjust the fuel level in the float chamber, adjust the idle system, unscrew, clean and blow the fuel jet of the idle system and its emulsion channel.

Difficult starting of a cold engine can be caused by a lack of fuel supply to the carburetor, a malfunction of the carburetor starting device, and a malfunction of the ignition system. If, with fuel supply to the carburetor and a good ignition system, a cold engine does not start well, possible cause there may be a violation of the adjustment of the position of the air and throttle valves of the primary chamber, as well as the pneumatic corrector of the starting device. In this case, it is necessary to adjust the position of the air damper by adjusting its cable drive and check the operation of the pneumatic corrector.

Engine runs erratically or stalls at low RPM crankshaft at idle. If the adjustment fails to achieve stable operation of the engine, then possible causes of the malfunction may be clogging of the jets and channels of the carburetor idle system, a malfunction of the EPHX system, as well as a violation of the tightness of the connections of the vacuum hoses of the EPHX system and vacuum booster brakes. In this case, it is necessary to check the tightness of the vacuum hose connections, unscrew the fuel jet of the idle system, blow it and the channels of the idle system through the hole from the inverted jet with compressed air (from a compressor or a tire pump with a cone nozzle) and repeat the adjustment of the idle system. On most carburetors, the idle jet can be unscrewed and purged, and the idle passages can be purged directly on the vehicle without removing the carburetor. Then the operation is checked and the EPHH system is adjusted. If these methods fail to restore the normal operation of the engine, then the carburetor should be removed from the car for repair.

Interruptions in the operation of the engine in all modes can be caused by clogging of the strainer, jets or carburetor channels, water ingress into it, air leakage through damaged gaskets in the connections of the carburetor with the inlet pipeline or through the hose going to the vacuum brake booster, a malfunction of the EPHH.

Increased fuel consumption can be caused by both fuel leakage and a malfunction of the carburetor - a violation of the idle system adjustment, incomplete opening of the air damper, an increase in the fuel level in the float chamber, as well as an increased throughput of jets. To identify and eliminate increased fuel consumption after a thorough external inspection of the fuel supply lines. elements of the power system adjust the idle system, check and adjust the opening of the air damper and the fuel level in the float chamber, check whether the jets of the main dosing systems of the carburetor are correctly installed and not mixed up in places. In addition, increased fuel consumption may occur due to a malfunction of other systems and mechanisms of the car (malfunctions of the ignition system, deterioration of the car roll due to a malfunction of the brake system, low tire pressure, etc.) Carburetor repair includes removing it from the car, dismantling, cleaning and purging with compressed air its parts and valves, checking parts, replacing failed parts, assembling the carburetor, as well as adjusting the fuel level in the float chamber and adjusting the idle system.

In many cases, it is possible to restore the carburetor's performance without removing it from the car and completely disassembling it by adjusting the idle system, the air damper actuator, turning out and cleaning its strainer, or with its partial disassembly - removing the cover, after which it is possible to adjust the fuel level in the float chamber and blow the jets. If it is impossible to restore the carburetor’s performance using the indicated methods, it is removed from the car, disassembled, washed, troubleshooted by cleaning contaminated jets and channels, as well as replacing failed parts (needle valve, diaphragms, gaskets, jets), assembled and, after installation on the car, they regulate idle system.

STATE BUDGET PROFESSIONAL EDUCATIONAL INSTITUTION OF THE MOSCOW REGION "RAMENSKY ROAD-BUILDING COLLEGE"

Final examination work

Profession: Car maintenance and repair master

student group: 18

FULL NAME:

Topic: Device, diagnostics, maintenance and repair of the power supply system of the carburetor engine GAZ, ZIL.

2017

1. Introduction

2. The device and principle of operation of the power supply system of the carburetor engine GAZ, ZIL

6. Repair of the power supply system of the carburetor engine GAZ, ZIL

1. Introduction

According to the cross-country ability, cars are divided into three groups: ordinary (road), high and high cross-country ability. The first of them (ZIL-130) are used mainly on the roads. Cross-country ability- GAZ-66 and ZIL-131 - can move on roads and off-road areas.

An engine is a machine that converts some form of energy into mechanical work. Engines in which thermal energy is converted into mechanical work are thermal.

Thermal energy is obtained by burning any fuel. An engine in which fuel burns directly inside the cylinder and the energy of the resulting gases is perceived by a piston moving in the cylinder is called a piston internal combustion engine. Such engines are mainly used in modern cars.

Consider the ZIL-130 engine:

The engine consists of a mechanism and systems that ensure its operation:

crank mechanism,

Gas distribution mechanism,

Cooling system,

Lubrication system,

Supply system.

In this paper, the power supply system of the ZIL carburetor engine is considered.

Purpose

All gasoline-powered engines have basically the same power system and operate on a combustible mixture consisting of fuel vapor and air. The power supply system includes devices designed for storing, cleaning and supplying fuel, air cleaning devices and a device used to prepare a combustible mixture from fuel vapor and air.

The power supply system of carburetor engines consists of fuel tank, sump , fuel pump, carburetor, air cleaner and intake manifold.

The preparation of the necessary combustible mixture from fuel and air takes place in a carburetor mounted on top of the engine on the intake pipe. The air entering the carburetor for the preparation of a combustible mixture is cleaned of dust in the air filter located directly on the carburetor or on the side of the engine. In this case, the air filter is connected to the carburetor by a pipe.

All fuel supply devices are interconnected by metal tubes - fuel lines that are attached to the frame or body of the car, and at the transition points from the frame or body to the engine - hoses made of special grades of gasoline-resistant rubber.

The carburetor is connected to the inlet channels of the engine cylinder head by means of an inlet pipe, and the exhaust channels are connected to the exhaust pipe, the latter is connected by a pipe to the exhaust silencer.

The K-88AM carburetor of the ZIL-130 engine has two mixing chambers, each of which serves four cylinders. When the engine is running at medium loads, fuel from the float chamber flows through the main jets, and then through the full power jets into the emulsion channels. In these channels, air is mixed with the fuel from the air jets and jets of the idle system. The resulting emulsion enters the mixing chambers through the annular slots of small diffusers. Maintaining a constant composition of the lean mixture occurs due to the deceleration of the fuel by air.

2.The device and principle of operation of the power supply system of the carburetor engine GAZ, ZIL.

2.1. The device and principle of operation of the power supply system GAZ, ZIL

The power supply system of the carburetor engine (Fig. 47) consists of a fuel tank 10, a fuel filter-sump 12, a fuel pump 1, a filter fine cleaning fuel 4, carburetor 3, air filter 2, inlet pipeline, exhaust pipeline 15, exhaust pipe 14 with exhaust silencer 13, connecting pipelines and petrol-resistant hoses 8, fuel intake valve 11;fuel level indicator in the fuel tank 9, throttle control pedal 7, control buttons for air 5 and throttle 6 carburetor dampers.

Fig.47. The power supply system of the carburetor engine.

When the engine is running, fuel from the fuel tank is forcibly supplied by the fuel pump to the carburetor float chamber, having previously been cleaned in the sediment filter and fine filter. At the same time, air pre-cleaned in the air filter enters the carburetor. In the carburetor, the fuel is mixed with air in a predetermined proportion and a combustible mixture is formed, which enters the engine cylinders through the intake pipeline, where it is compressed, ignited and burned, releasing thermal energy, which, with the help of mechanisms and systems, is converted into mechanical energy and transmitted in the form of torque to the engine. the wheels of the car, setting it in motion. Exhaust gases are discharged to the atmosphere through the exhaust pipeline.

2.2. The device and purpose of the power supply system GAZ, ZIL

Power system devices. All gasoline-powered engines have basically the same power system and operate on a combustible mixture consisting of fuel vapor and air. The power supply system includes devices designed for storing, cleaning and supplying fuel, air cleaning devices and a device used to prepare a combustible mixture from fuel vapor and air.

The fuel is placed in a fuel tank, the capacity of which is sufficient to operate the vehicle during one shift. The fuel tank of the truck is located on the side of the vehicle on the frame.

From the fuel tank, the fuel enters the fuel filters-settlers, in which mechanical impurities and water are separated from the fuel. The sediment filter is located on the frame near the fuel tank. The fuel supply from the tank through the fine filter to the carburetor is carried out by a fuel pump located on the engine crankcase between the rows of cylinders on top of the engine.

The preparation of the necessary combustible mixture from fuel and air takes place in a carburetor mounted on top of the engine on the intake pipe. The air entering the carburetor for the preparation of a combustible mixture is cleaned of dust in the air filter located directly on the carburetor or on the side of the engine. In this case, the air filter is connected to the carburetor by a pipe.

All fuel supply devices are interconnected by metal tubes - fuel lines that are attached to the frame or body of the car, and at the transition points from the frame or body to the engine - hoses made of special grades of gasoline-resistant rubber.

Carburetoris connected to the inlet channels of the engine cylinder head by means of an inlet pipeline, and the exhaust channels are connected to the exhaust pipeline, the latter is connected by a pipe to the exhaust silencer.

To prevent the possibility of the engine running at an excessively high crankshaft speed, a crankshaft speed limiter is included in the power supply system of trucks.

The K-88AM carburetor of the ZIL-130 engine has two mixing chambers, each of which serves four cylinders. When the engine is running at medium loads, fuel from the float chamber flows through the main jets, and then through the full power jets into the emulsion channels (Fig. 19). In these channels, air is mixed with the fuel from the air jets and jets of the idle system. The resulting emulsion enters the mixing chambers through the annular slots of small diffusers. Maintaining a constant composition of the lean mixture occurs due to the deceleration of the fuel by air.

Fuel pump. On cars, the carburetor is located above the fuel tank and the fuel supply is forced. For forced supply of fuel from the tank to the carburetor, a diaphragm-type fuel pump is installed on the engine.

The pump (fig. 20) consists of three main parts! housings, heads and covers. In the housing on the axis there is a two-arm lever with a return spring and a manual pumping lever. A diaphragm is fixed between the casing and the pump head, assembled on a rod having two plates. The two-arm lever acts on the rod through a textolite thrust washer. A pressure spring is installed under the diaphragm.

The pump head has two inlet and one outlet valves. The valves have a guide rod, a rubber washer and a spring. On top of the intake valves is a strainer.

The diaphragm type fuel pump is driven directly from the camshaft eccentric.

When an eccentric or rod runs into the outer end of the two-arm lever, its inner end, moving, bends the diaphragm down and a vacuum is created above it (see Fig. 20, a). Under the action of the vacuum created, the fuel from the tank enters through the pipeline to the pump inlet and passes through the strainer to the inlet valves, while the pump pressure spring is compressed. When the protrusion of the eccentric comes off the outer end of the two-arm lever, the diaphragm moves upward under the action of the pressure spring and pressure is created in the chamber above it. Fuel is forced out through the delivery valve into the outlet channel and then through the tube into the carburetor float chamber (see Fig. 20, b).

To reduce fuel pulsation, there is an air chamber above the delivery valve. When the pump is operating, pressure is created in this chamber, due to which fuel is supplied to the carburetor evenly. The capacity of the fuel pump is designed to operate at maximum fuel flow, however, in reality, the amount of fuel supplied should be less than the capacity of the pump.

When the float chamber is filled, the needle valve closes the hole in the seat and pressure is created in the fuel line from the pump to the carburetor, which spreads into the cavity above the diaphragm. In this case, the pump diaphragm remains in the lower position, since the pressure spring cannot overcome the pressure created, and the two-arm lever swings idle under the action of the eccentric and return spring.

To fill the float chamber of the carburetor with fuel when the engine is not running, use the manual priming lever located on the side of the pump housing. The lever has a roller with a cut off part and a return spring. In the depressed position, the cut of the roller is above the rocker arm and does not affect it. When moving the manual pumping lever, the roller, with the edges of the cut-out part, presses on the inner end of the two-arm lever and moves the diaphragm down.

The manual inflation lever can be used when the eccentric has released the outer end of the two-arm lever.

Fuel filters and sedimentation tanks . The fuel supplied to the carburetor jets should not have mechanical impurities and water, since impurities clog the holes of the jets, and water frozen in winter will cause the fuel supply to stop. To clean the fuel in the engine power system, the installation of filters and sedimentation tanks is provided. Mesh filters are installed in the filler necks of fuel tanks, in the diaphragm pump housing and in the inlet fittings of the carburetor float chamber.

On trucks, two sediment filters are additionally included in the power supply system. One of the coarse filters-settlers is installed at the fuel tank. This filter (Fig. 21, a) consists of a cover and a removable housing. Inside the housing, on racks, there is a filter element from a set of thin filter plates with stamped protrusions 0.05 mm high, so a gap of 0.05 mm wide remains between the plates. Fuel from the tank enters through the inlet into the filter sump. Since the sump has a larger volume than the fuel line, the speed of the incoming fuel is sharply reduced, which leads to the deposition of mechanical impurities and water.

Fuel, passing through the slots of the filter element, is additionally cleaned of mechanical impurities that settle on the filter element.

The fuel fine filter (Fig. 21, b) is installed in front of the carburetor. It consists of a body, a sump cup, a filter element with a spring and a cup clamp. The filter element can be made of ceramic or fine mesh rolled up.

The fuel supplied by the diaphragm pump enters the settling glass. Some of the mechanical impurities precipitate in the settling glass, while the remaining impurities are retained on the surface of the filter element.

Fuel coarse filter installed at the fuel tank and is designed for preliminary cleaning of the fuel entering the fuel booster pump. It consists of a housing, a sump, a cover with inlet fittings, a mesh filter element, a drain plug and an air outlet plug from the system.

Fine fuel filter designed to clean the fuel from small particles. It consists of two caps, a cover and two filter elements. A drain plug is screwed into the bottom of each cap. The replaceable filter element is made of paper. The filter cap has a drain valve through which part of the fuel is drained along with the air that has entered the low pressure system.

Air filter. The car is often operated in conditions of strong air pollution. Dust, getting into the engine cylinders along with air, causes accelerated wear of both cylinders and piston rings. Purification of the air supplied for the preparation of a combustible mixture is carried out in the air filter.

On the ZIL-130 car, air filters of the inertial-oil type are used. The filter (Fig. 22) consists of an oil bath body, a cover with a pipe, a filter element made of a metal mesh or nylon fiber, a coupling screw with a wing nut.

Under the action of vacuum created by a running engine, air enters the inlet annular slot through the pipe and, moving down it, hits the oil, to which large dust particles adhere. With further movement, the air picks up oil particles and wets the filter element with it. Oil flowing from the filter element washes away dust particles that have settled on the reflector. The air passing through the filter element is completely cleaned of mechanical impurities and enters the carburetor mixing chamber through the central pipe.

The filter is installed using an adapter pipe directly on the carburetor and connected to the carburetor using an air pipe.

Fuel tank. A fuel tank is installed to store the fuel supply necessary for the operation of the car. It consists of two halves, stamped from sheet steel and connected by welding. Inside the tank, to increase rigidity and reduce fuel shock whenits movement, partitions are installed. The tank has a filler neck with a plug, in which two valves are located, the action of which is similar to the action of the steam-air valves of the radiator cap.

Fuel tank diesel car similar in design to the fuel tank of a gasoline-powered car, but there are no valves in the plug. To prevent rarefaction in the tank during fuel production, a tube is installed from it in the upper part, which communicates the internal cavity of the tank with the atmosphere.

A fuel gauge sensor and a fitting with a tap and a suction pipe are installed on top of the tank. The intake tube at the bottom ends with a mesh filter. At the bottom of the tank there is drainer closed with a screw plug.

The capacity of the fuel tank of the car is as follows: ZIL-130-170 l.

intake pipes . The supply of a combustible mixture from the carburetor to the engine cylinders is carried out through the inlet pipeline.

The inlet pipeline of the ZIL-130 engine is cast from aluminum alloy and fixed to the heads of the right and left rows of cylinders. The intake pipeline has a complex system of channels through which the combustible mixture is supplied to the cylinders. Between the inlet channels of the inlet pipeline there is a space communicated with the cooling cavity of the cylinder heads.

Gaskets are installed to seal the junctions between the intake manifold and the cylinder heads.

Exhaust pipes . They serve to remove exhaust gases from the engine cylinders, they are made separately and attached to the outside of the cylinder heads.

To reduce the resistance to the passage of the combustible mixture and exhaust gases, the channels of the inlet and outlet pipelines are made shorter and with smooth transitions.The exhaust pipelines are sealed with metal-asbestos gaskets, and they are fixed on studs with nuts.

Heating of the combustible mixture . The process of preparing a combustible mixture does not end in the mixing chamber of the carburetor, but continues in the intake manifold and engine cylinders. For better evaporation of fuel during engine operation, the intake manifold is heated. The heating of the inlet pipeline is especially necessary when operating the car in cold weather and at the time of starting its engine. However, excessive heating of the combustible mixture is undesirable, since in this case the volume of the mixture increases, and the weight filling of the cylinders decreases.

In the ZIL-130 engine, the combustible mixture is heated due to the heat given off by the circulating liquid in the cooling cavity of the inlet pipeline. When starting these engines at low temperatures, it is possible to heat the inlet pipeline due to the hot water through the cooling system.

3. Diagnostics of the power supply system of the carburetor engine GAZ, ZIL

Diagnostic signs of malfunctions of the power system are: difficulty starting the engine, increased fuel consumption under load, a drop in engine power and overheating, a change in the composition and an increase in the toxicity of exhaust gases.

Diagnosis of the power supply system of diesel and carburetor engines is carried out by the methods of running and bench tests.

When diagnosing by the method of sea trials determine the fuel consumption when the car is moving at a constant speed on a measured horizontal section of the road with low traffic intensity in both directions.

The control fuel consumption is determined for trucks at a constant speed of 30-40 km/h and for cars - at a speed of 40-80 km/h. The amount of fuel consumed is measured by flow meters, which are used not only to diagnose the power system, but also to teach drivers how to drive economically.

Diagnosis of the vehicle's power system can be carried out simultaneously with testing the traction characteristics of the vehicle on a bench with running drums, which significantly reduces time losses and eliminates the inconvenience of the sea trial method. To do this, the car is installed on the stand in such a way that the drive wheels rest on the running drums. Before measuring fuel consumption, preheat the engine and transmission of the car for 15 minutes. at a speed of 40 km / h in direct gear and at full throttle, for which a load is created on the drive wheels by the load device of the stand. After that, for carburetor engines, the operation of the fuel pump is checked (if the stand with running drums is not equipped with a pressure gauge to control the operation of the fuel pump) with a model 527B instrument for the pressure it develops and the tightness of the carburetor float chamber valve. The pressure is measured at a low engine speed and with the shut-off valve open. The results of the check are compared with the data of the table placed on the cover of the instrument case, and, if necessary, troubleshooting is carried out.

4. Maintenance of the power supply system of the carburetor engine GAZ, ZIL

Daily Maintenance (EO):

Clean the engine of dirt;

Check the condition of the engine by external inspection and listen to its operation in different modes;

Check the fluid level in the radiator;

-check for fluid and oil leaks;

Check the oil level before starting the engine;

Visually check the tightness of the fuel lines.

Maintenance No. 1 (TO-1):

Check the fastening of the engine mounts;

Check the tightness of the connection of the cylinder head, oil pan, crankshaft oil seal;

Rinse the air filter;

Lubricate the distributor breaker shaft.

Maintenance No. 2 (TO-2):

Tighten the cylinder head nuts;

Check the gap between the valve stems and the toe of the rocker arm;

Check for fluid leakage in the entire cooling system;

Lubricate water pump bearings;

Check the fastening of the radiator and shutters;

Check water pump mounting and belt tension;

Check the operation of the steam-air valve of the radiator plug;

Replace filter elements;

Inspection to check the tightness of all devices of the lubrication system;

Drain the sediment from the oil filter;

Change the oil in the crankcase;

Check the oil level in the crankcase;

Check the operation of the fuel pump using a pressure gauge;

Check the tightness of all connections in the power system;

Check drive throttle valve;

Rinse the air filter;

Check the fuel level in the carburetor float chamber;

Clean the surface of the ignition system devices from dust and dirt and oil;

Check spark plugs and distributor breaker

5. The main malfunctions of the power supply system of the carburetor engine GAZ, ZIL

Malfunction	Cause	Solutions
No fuel supply	Clogged filters or fuel lines, malfunction of the fuel pump or carburetor.	Clean or replace filters, fuel lines Replace or repair fuel pump/carburetor
Combustible mixture lean	Reduce fuel supply or increase air intake	Increase fuel supply Restrict air intake
Rich combustible mixture	Incomplete opening of the air damper, increased fuel level in the float chamber, sticking of the float or fuel supply valve in the open position, enlargement of the holes of the jets, clogging of the air jet, leakage of the float, fuel supply valves, economizer valves.	Check and correct/adjust the air damper. Reduce fuel supply. Adjust float; adjust valves. Check tightness, seal.
Unstable engine operation	Violation engine speed adjustment. Piston sticking, actuator failure, check valve leaking, nozzle clogged, delivery valve stuck	Adjust the engine speed. Carry out the necessary engine maintenance operations.
Engine power drop	Incomplete throttle opening when the pedal is pressed all the way and clogged air filter	Adjust or replace throttle valve. Clean the air filter.
Increased fuel consumption	Flow through leaks in the fuel-line connections or a damaged fuel pump diaphragm.	Check connections (tighten if necessary). Check diaphragm (replace if necessary).

6. Repair of the power supply system of the carburetor engine GAZ, ZIL

7. Security requirements. For vehicle maintenance and repair

All work on the maintenance and repair of the car should be carried out at specially equipped posts.

When installing the car at the service station, you should slow it down parking brake, turn off the ignition, turn on the lowest gear in the gearbox and place at least two stops under the wheels.

Before performing control and adjustment operations on a non-working engine (checking the operation of the generator, adjusting the carburetor, relay-regulator, etc.), check and fasten the cuffs of the sleeves, remove the hanging ends of the clothing, tuck the hair under the headgear, while working while sitting on fender or buffer of the machine.

A sign is posted on the steering wheel "Keep out - people are working." When removing components and parts that require great physical effort, it is necessary to use devices (pullers). During work related to turning the engine crankshaft, it is necessary to additionally check the ignition is turned off, and set the gear lever to the neutral position. When starting the engine manually, you should beware of kickbacks and use the correct grip on the starting handle (do not grab the handle, turn it from the bottom up). When using a heater Special attention refers to its serviceability, the absence of gasoline leaks; the operating heater must not be left unattended. The tap of the fuel tank of the heater is opened only during its operation; in the summer, the fuel is drained from the tank.

Do not service the transmission while the engine is running. When servicing the transmission outside the inspection ditch or overpass, it is necessary to use sunbeds (bedding). For work related to turning cardan shafts, you must additionally make sure that the ignition is turned off, put the gear lever in neutral and release the parking brake. After completing the work, re-apply the parking brake and engage a low gear in the gearbox.

When removing and setting the springs, you must first unload them by raising the frame and installing it on the goats. When removing the wheels, you should also put the car on the goats, and place stops under the unremoved wheels. It is prohibited to carry out any work on a car hung only on lifting mechanisms (jacks, hoists, etc.). Wheel disks, bricks, stones and other foreign objects must not be placed under the suspended vehicle.

The tool used in the maintenance and repair of the car must be in good working order. Hammers and files should have well-fitted wooden handles. Unscrewing and tightening nuts should be done only with serviceable wrenches of the appropriate size.

After completing all the work, before starting the engine and starting the machine, you need to make sure that all the people involved in the work are at a safe distance, and the equipment and tools are removed in their places.

Checking and testing on the go of the steering and braking systems must be carried out on an equipped site. The presence of unauthorized persons during the check of the car on the move, as well as the placement of persons participating in the check on the steps, fenders is prohibited.

When working on inspection ditches and lifting devices, the following requirements must be met:

when placing the machine on the inspection ditch (overpass), drive the machine at low speed and monitor the correct position of the wheels relative to the guide flanges of the inspection ditch; the machine placed on the inspection ditch or lifting device should be braked with a parking brake and chocks should be placed under the wheels; portable lamps in the inspection ditch can only be used with a voltage not higher than 12 V; do not smoke or light open flames under the car; do not put tools and parts on the frame, steps and other places from where they can fall on workers; before leaving the ditch (overpass), make sure that there are no people under the machine, uncleaned tools or equipment; beware of poisoning by exhaust gases and fuel vapors accumulating in the inspection ditches.

When working with gasoline, you must follow the rules for handling it. Gasoline is a highly flammable liquid, causes irritation when it comes into contact with the skin, dissolves paint well. Care should be taken when handling gasoline containers, as its vapors remaining in the container are highly flammable. Particular care should be exercised when working with ethyl rosean gasoline, which contains a potent substance - tetraethyl lead, which causes severe poisoning of the body. Do not use leaded gasoline for washing hands, parts, cleaning clothes. It is forbidden to suck up gasoline and blow out pipelines and other devices of the fuel system by mouth. You can store and transport gasoline only in closed containers with the inscription "Leaded gasoline is poisonous." Use sawdust, sand, bleach, or warm water to clean up spilled gasoline. Skin areas doused with gasoline are immediately washed with kerosene, and then with warm water and soap. Before eating, be sure to wash your hands.

Special care must be taken when handling antifreeze. This liquid contains a potent poison - ethylene glycol, the entry of which into the body leads to severe poisoning. The container in which antifreeze is stored and transported must have the inscription "Poison" and be sealed. It is strictly forbidden to pour low-freezing liquids with a hose by suction by mouth. Filling the car with antifreeze is done directly into the cooling system. Wash your hands thoroughly after servicing a cooling system filled with antifreeze. In case of accidental ingestion of antifreeze into the body, the victim must be immediately taken to a medical center for assistance.

brake fluids and their vapors can also cause poisoning if ingested, so all precautions must be taken when handling these liquids, and hands should be thoroughly washed after handling them.

Acids are stored and transported in glass bottles with ground stoppers. The bottles are installed in soft wicker baskets with wood shavings. When carrying bottles, stretchers and carts are used. Acids on contact with skin cause severe burns and destroy clothing. If acid gets on the skin, quickly wipe this area of ​​​​the body and rinse with a strong stream of water.

Solvents and paints cause irritation and burns when in contact with the skin, and their vapors can cause poisoning if inhaled. Car painting should be done in a well ventilated area. Wash hands thoroughly with soap and warm water after handling acids, paints and solvents.

Exhaust gases leaving the engine contain carbon monoxide, carbon dioxide and other substances that can cause severe poisoning and even death. Drivers should always remember this and take measures to prevent exhaust gas poisoning.

The engine power system devices must be properly adjusted. Periodically check the tightness of the exhaust pipe fastening nuts. When performing inspection and adjustment work related to the need to start the engine in a closed room, it is necessary to ensure the removal of gases from the muffler; performance of these works in rooms not equipped with ventilation is prohibited.

It is strictly forbidden to sleep in the cab of a car with the engine running, in such cases exhaust gases seeping into the cab often lead to fatal poisoning.

When working with a power tool, it is necessary to check the serviceability and availability of protective grounding. The voltage of portable lighting used in the maintenance and repair of vehicles should be no more than 12 V. When working with a tool powered by a voltage of 127-220 V, wear protective gloves and use a rubber mat or dry wooden platform. leaving workplace even for a short time, it is necessary to switch off the instrument. In the event of any malfunction of the power tool, grounding device or socket outlet, work must be stopped.

When mounting and dismounting tires, the following rules must be observed: mounting and dismantling of tires must be carried out on stands or a clean floor (platform), and in the field - on a spread tarpaulin or other bedding; before dismantling the tire from the wheel rim, the air from the chamber must be completely released, the dismantling of the tire adhering to the rim must be carried out on a special tire dismantling stand;it is prohibited to mount tires on faulty wheel rims, as well as to use tires that do not match the size of the wheel rim; when inflating a tire, it is necessary to use a special guard or safety devices; when performing this operation in the field, you need to put the wheel with the lock ring down.

The driver must know the causes and rules for extinguishing a fire in the park and in the car. It is necessary to monitor the serviceability of electrical equipment and the absence of fuel leakage. If the car catches fire, it should be immediately removed from the parking lot and measures should be taken to extinguish the flame. To extinguish a fire, use a thick foam or carbon dioxide fire extinguisher, sand, or cover the fire with a dense cloth. In the event of a fire, regardless of the measures taken, the fire brigade must be called.

8. List of used literature

Introduction

The device of the power supply system of the carburetor engine

1.1 Purpose of the power supply system of the carburetor engine

1.2 Main characteristics and working principle

3 Materials used in the manufacture, maintenance and repair

2. Maintenance and repair of the power supply system of the carburetor engine

2.1 List of work performed in the scope of ETO, TO-1, TO-2 and STO

2.2 Malfunctions of the power supply system of the carburetor engine. Causes of their occurrence and ways to eliminate them

2 Assembly and disassembly work carried out during the repair process

3. Safe organization of work

Conclusion

Bibliography

Introduction

Road transport is of great importance as it serves all industries. In our country, the range of transportation of goods and passengers is constantly increasing due to the improvement in the performance of cars, the improvement of automobile roads and the construction of new ones.

In order to successfully solve the tasks set by road transport, it is necessary to constantly maintain cars in good technical condition, create a maintenance organization that would provide for the timely and high-quality performance of all car care operations. In this case, it is necessary to use the correct methods for performing each operation and widely use mechanization. Qualified performance of maintenance works ensures trouble-free operation of aggregates, components and systems of vehicles, increases their reliability and maximum overhaul runs, increases productivity, reduces fuel consumption, reduces the cost of transportation, and improves traffic safety.

The development and improvement of car repair production require the proper organization of car repair, which in turn depends on a number of factors, the most important of which is the rational distribution of repair enterprises, their specialization and production capacity. The efficiency of the use of motor vehicles depends on the perfection of the organization of the transport process and the properties of vehicles to maintain within certain limits the values ​​of parameters characterizing their ability to perform the required functions. During the operation of the car, its functional properties gradually deteriorate due to wear, corrosion, damage to parts, fatigue of the material from which they are made, etc. Various malfunctions appear in the car, which reduce the efficiency of its use.

To prevent the appearance of defects and timely eliminate them, the car is subjected to maintenance (TO) and repair. TO is a complex of operations or an operation to maintain the operability or serviceability of a car when used for its intended purpose during parking, storage or transportation.

1. The device of the power supply system of the carburetor engine

The power supply system (Fig. 1) consists of:

fuel tank - 2,

Fuel lines - 5,

fuel purification filters - 6,

fuel pump - 7,

air filter - 9, carburetor:

8 - float chamber of the carburetor with a float;

Mixing chamber of the carburetor;

Inlet valve;

intake pipeline;

The combustion chamber

Rice. 1. The layout of the elements of the power system

Fuel pump(fig. 2) - diaphragm, with the upper location of the sump, driven by an eccentric camshaft. The pump housing consists of two parts - upper 3 and lower 4, - cast from zinc alloy. A 1" diaphragm is sandwiched between them, consisting of four layers of fabric impregnated with petrol-resistant varnish.

In the center of the diaphragm, with the help of two washers, a rod 7 is fastened, which has an eyelet at the lower end, into which the lever 8 of the rod enters. The lever 8 of the thrust and the lever 14 of the pump drive are mounted on a common axis 12. The drive lever at one end rests against the thrust lever, the other end against the eccentric 15 of the camshaft.

The drive lever is constantly pressed against the eccentric by the spring 13, installed between the protrusions on the lower part of the housing and on the lever. A spring 5 is placed under the diaphragm, returning its upper position.

The thrust is sealed with an oil seal 16, which prevents the penetration of gases and, together with them, drops of oil from the engine crankcase into the cavity under the diaphragm. This cavity is connected to the atmosphere through hole 6.

In the two tides of the housing there is a roller 9 of the lever 10 of manual pumping. The roller is sealed on both sides with oil and petrol resistant rubber rings.

In the upper part of the housing there are non-separable pressure (outlet) 22 and inlet 21 valves. The valves are fixed in the body with a pressure plate and two screws. A filter 23 is installed above the intake channel of the inlet valve. From above, the body is covered with a glass sump cup 24, sealed with a rubber gasket 20 and pressed against the body with a screw, a wing nut 25 and a wire bracket. A transparent glass allows you to observe the amount of sludge accumulated in it and clean it in time.

Rice. 2. Fuel pump

1.1 Purpose of the power supply system of the carburetor engine

The power supply system of a carburetor engine is designed to store fuel, provide and purify fuel and air, cook fuel mixture of the desired composition and quality and providing it in the required quantity to the engine cylinders, as well as for venting combustion products into the atmosphere, cleaning exhaust gases and damping noise at the air inlet and exhaust gases.

The mixture of gasoline and air vapors formed in a carburetor is called a combustible mixture. This mixture is fed into the engine cylinders, where it mixes with the residual exhaust gases, such a mixture is called the working mixture.

It has been established that 15 kg of air is needed to burn 1 kg of fuel. A mixture of this composition is called normal. However, at a ratio of 1:15, complete combustion of the fuel does not occur and part of it is lost. For complete combustion, the ratio of fuel and air must be 1:17 ... 1:18, such a mixture is called lean. Due to the excess air in the lunch mixture, its calorific value decreases, which leads to a decrease in the combustion rate and engine power. To increase engine power, the mixture must burn at the highest speed, and this is possible with a fuel-to-air ratio of 1:13, such a mixture is called enriched. With this composition of the mixture, complete combustion of the fuel does not occur and the efficiency of the engine deteriorates, but it is possible to get the most power from it.

Fuel tank(Fig. 3.) is a fuel storage tank. It is usually located in the rear, safer part of the car.

Fuel filter(Fig. 4.) is designed for fine cleaning of gasoline supplied to the fuel pump (it is possible to install a filter after the pump).

Rice. 3. Fuel tank

Rice. 4. Fuel filter

Jet (Fig. 5) designed for dosing and supplying fuel or gas.

Rice. 5. Jets

Carburetor- provides the required amount of fuel and air in the mixture that enters the chambers of the internal combustion engine.

Carburetor (K-22I) The K-22I carburetor is single-chamber, three-diffuser, with a balanced float chamber. According to the method of compensating the mixture in the main dosing system, it belongs to carburetors with regulation of vacuum in the diffuser and the inclusion of an additional (compensation) jet.

The scheme is shown in fig. 6.

Rice. 6. Diagram of the carburetor

.2 Main characteristics and principle of operation

Technical characteristics of the K-22I carburetor

Throughput of jets, cm 3 / min .:

main - 220 ±5

compensatory - 325±3

fuel idle52 ± 3

Jet diameter, mm:

air idle (two) 1 ,4+ 0.1

emulsion idle 1 + 0.1

power 0.9+ 0.06

Nozzle diameter accelerator pump, mm - 0.7+ 0.06

Opening the adjusting needle of the main jet (from the fully closed position):

during vehicle operation - 1 3/4 -2

The volume of the fuel tank GAZ-21 - 55l

Principle of operation

In such a power system, the preparation of a combustible mixture of the required composition occurs in the carburetor, then the combustible mixture in the required amount enters directly into the engine cylinders.

The tank stores the supply of fuel necessary for the operation of the engine, fuel is supplied to the carburetor from the tank by the fuel pump through the fuel lines. The use of a fuel pump allows the fuel tank to be located in any part of the vehicle. The filter-sump is designed to purify fuel from mechanical impurities and water. Atmospheric air enters the carburetor through the air filter, where it is cleaned of dust. The carburetor prepares the working mixture that enters the engine cylinders through the intake manifold. The exhaust manifold is required to remove exhaust gases from the cylinders. Exhaust gases through the exhaust manifold enter the muffler to reduce noise, after which they are released into the atmosphere.

Fuel enters the float chamber through the fuel line, the float chamber is connected to the mixing chamber by a spray gun, where the jet is installed. The float uses a needle valve to maintain a constant fuel level in the float chamber. As soon as the float chamber is filled, the float floats up, raising the needle valve with the help of a lever, the needle valve, in turn, closes the hole in the fuel supply line, blocking it, and fuel access to the chamber is stopped.

Air, passing through the carburetor, enters the narrow section of the diffuser where its speed increases. Due to the increase in the speed of the air flow passing through the diffuser, the vacuum increases in it. A pressure difference is created between the float chamber and the diffuser, as a result of which the fuel enters the mixing chamber through the jet, forming a combustible mixture. Next, the combustible mixture enters the engine cylinder. After combustion of the working mixture, the exhaust gases are discharged through the exhaust valve. The exhaust gases pass through the muffler and are discharged into the atmosphere.

Rice. 7. The principle of operation of the power supply system of the carburetor engine

1.3 Materials used in the manufacture, maintenance and repair

Carburetor bodies are made by injection molding of zinc alloys having low temperature melting and good casting properties, which makes it possible to obtain castings of high accuracy, the required density, clean surface and sufficient mechanical properties. In the USA, zinc alloys are used for the manufacture of carburetor parts, which, in their chemical composition and properties, are close to zinc alloys, which are used in the USSR. The float mechanism is made by stamping and brass tape, sufficiently resistant to the corrosive effects of fuel. The material used for the valves is stainless steel, which, when used in a brass body, ensures a long service life. As a material for jets, nozzles and other dosing elements, brass is most widely used.

Most often, the fuel housing is made by injection molding from zinc, aluminum and magnesium alloys. Fuel pump diaphragms are usually made of cotton or nylon coated with synthetic rubber. The fuel pump drive mechanism is made of carbon and low alloy steel (for example, grade 45). The diaphragm spring is made of carbon spring steel.

For the manufacture of filter elements, brass grades L68, L62 and L59-1 are used. The housing of the fuel fine filter is cast under pressure from aluminum or zinc alloys. The settling glass is most often made of glass, Bakelite or polystyrene.

The body parts of the air cleaner are made of tinned or lead-coated steel.

Tank parts are made of leaded or galvanized steel. Copper is used in the manufacture of the fuel line.

power system carburettor engine

2. Maintenance and repair

.1 List of work performed in the scope of STO, TO-1, TO-2 and STO

ETO. Check the fuel level in the tank and fill the vehicle with fuel. Visually check the tightness of the connection of the carburetor, fuel pump, fuel lines and fuel tank.

TO-1. Check by external inspection the tightness of the connections of the power supply system; troubleshoot if necessary. Check the connection of the pedal lever to the throttle shaft and the cable to the air damper lever, the operation of the drives and the completeness of opening and closing the throttle and air dampers. The drive pedal should move smoothly in both directions. After operating the vehicle on dusty roads, wash the carburetor air filter and change the oil in it.

TO-2. Check the tightness of the fuel tank and the connections of the pipelines of the power system, the fastening of the carburetor and the fuel pump; troubleshoot if necessary. Check the connection of the rod to the throttle lever and the cable to the air damper lever, the operation of the actuators, the completeness of opening and closing the throttle and air dampers. Check the operation of the fuel pump with a pressure gauge (without removing it from the engine). The pressure created by the pump must be within 0.03 ... 0.04 MPa. Check the fuel level in the carburetor float chamber when the engine is running at low idle speed. Wash the engine air filter and change the oil in it.

ONE HUNDRED. Twice a year, remove the carburetor from the engine, disassemble and clean it. Flush and check the operation of the engine speed limiter. When preparing for winter operation, check on special devices the carburetor, its components and parts, including jets. Remove the fuel pump, disassemble it, clean and check the condition of the parts. After assembly, check the fuel pump on a special device. Drain the sediment from the fuel tank twice a year and once a year (when changing to winter operation) flush the tank.

Maintenance of carburetors. Reliability in the operation of the carburetor is achieved by performing the following operations.

Cleaning and flushing the carburetor. The carburetor is removed from the engine and disassembled, resinous deposits are removed, the parts are washed with a hair brush in a bath of aviation gasoline or acetone, the jets and channels in the body are blown with compressed air. Do not use wire, metal objects or cleaning materials to clean the jets. When working on leaded gasoline, before cleaning the carburetor parts, they must be immersed for 10-20 minutes in kerosene or another solvent. When assembling the carburetor, check the condition of all gaskets and replace the unusable ones. In order to avoid damage to the float, it is not allowed to blow the assembled carburetor with compressed air through the fuel supply fitting or balancing tube.

The throttle and air damper are not removed when disassembling the carburetor. After assembling the carburetor, you need to make sure that they turn without jamming.

Checking the tightness of the float is carried out by immersing it for 30 seconds in water heated to a temperature of 80-90°C. If the float fails, air bubbles will come out of it. Such a float must be replaced or soldered, after removing the fuel that has entered it. After soldering, check the weight of the float.

The tightness test of the needle valve is carried out on a vacuum device. The tank of the device is filled with distilled water, and the test valve assembly with the seat is installed on the gaskets in the body. Then, using the pump piston, a vacuum is created in the control tube, raising the level of the water column to 1000 mm, and the valve is closed. At the same time, a vacuum is created in the tee 6 under the tested valve.

The tightness of the valve is considered satisfactory if the water level in the control tube drops by no more than 10 mm within 30 seconds. If the water level drops more, the valve must be lapped or replaced.

The fuel level in the float chamber can be checked without removing the carburetor from the engine or by installing the carburetor on a special device.

Checking the throughput of jets is carried out once a year in a planned manner, as well as during the next maintenance of the car in case of excessive fuel consumption.

The capacity of the jets is determined by the amount of distilled water (in cm 3) flowing through the metering hole of the jet in 1 min under the pressure of a water column 1 ± 0.002 m high at a water temperature of 20 ± 1C. Checking (calibration) of jets is carried out on devices that, according to the principle of measuring the amount of water, are divided into two groups: with absolute and relative measurement.

Fuel Pump Service. Reliable fuel supply to the carburetor in various engine operating modes can be disrupted due to damage to the fuel pump diaphragm, loss of elasticity of its spring, gumming and sticking of valves, contamination of the filter mesh and loss of pump tightness.

In pumps with a settling cup, fuel may leak through the gasket between the housing and the settling cup. If the leak does not stop after tighter tightening of the fastening lamb, it is necessary to change the gasket.

Fuel leaking out of the opening of the pump housing or when the control plug is unscrewed in the housing for sealed pumps indicates damage to the diaphragm, which should be replaced.

The easiest way to check the operation of the pump without removing it from the engine is to use manual pumping. A serviceable pump should continuously supply a strong pulsating stream of fuel without foam from the pump fitting disconnected from the fuel line going to the carburetor. The presence of foam indicates air leakage in the line.

Air filter care. The frequency of maintenance of the air filter depends on the operating conditions. Care consists in washing the filter and changing the oil. Under normal operating conditions, this operation is carried out at TO-2, in difficult road conditions - at TO-1, and in conditions of high dust content of the air - every other day. For washing, the air filter is removed from the engine, the contaminated oil is drained from its bath, the filter parts are washed in kerosene or gasoline, then they are wiped, and the filter element is dried with compressed air. The filter element is moistened with the oil used for the engine, and oil is poured into the housing to the specified level.

In air filters connected to the engine crankcase ventilation system, simultaneously with cleaning the ventilation system, it is also necessary to clean the air cavity of the filter from resinous deposits, and immerse the metal filter element in acetone for 20-30 minutes, then blow it with compressed air. When working at low temperatures (from -20° to -40°), it is necessary to fill the filter with AC oil, which has a low pour point. At temperatures below -40° in snowless winter conditions, up to 20% of kerosene should be added to the oil poured into the filter.

After assembling the filter, do not start the engine for 10 - 15 minutes in order for excess oil to drain from the filter element.

Fuel filter maintenance. The care of the sedimentation filter consists in checking its tightness, releasing the sludge and washing it.

To release the sludge, it is necessary, having previously closed the valve from the fuel tank and loosened the coupling bolt, unscrew the plug. After the sludge is released, the tank valve is opened for a time sufficient to rinse the filter housing with clean gasoline.

To wash the sediment filter, remove the housing and filter element, wash them in unleaded gasoline and dry. To avoid damage to the filter plates, do not use brushes, scrapers, or high-pressure compressed air when cleaning them. During assembly, check the condition of the gaskets. The tightness of the assembled sump filter is checked under pressure (2 kg/cm 2 ) 196 133 N/m 2 .

In the fine fuel filter, a sump glass and a ceramic or nylon filter element are removed and thoroughly washed in gasoline.

Maintenance of the fuel tank and fuel lines. The tightness of the fuel lines in the area from the tank to the fuel pump should be checked with the engine off, and in the area from the pump to the carburetor - with the engine running, when pressure is created in the fuel line. Detected fuel leakage is eliminated by tightening the nuts of the connections or replacing faulty nuts, fittings and fuel lines.

.2 Malfunctions of the power supply system of the carburetor engine. Causes of their occurrence and ways to eliminate them

Fuel not getting to carburetor due to clogging of the compensation hole in the fuel tank cap (or tank vent pipe), excessive clogging of the fuel intake filter or fine filter. Malfunctions of the fuel pump are also possible: damage to the diaphragm or its spring, as well as “hanging” or not tightly closing the valves.

To eliminate the malfunction, all the mentioned elements of the power system should be checked sequentially. Then rinse and put in place everything that is in good order, and replace the faulty components and parts with new ones.

Engine does not develop full power and/or runs erratically due to a violation of the fuel level in the float chamber, contamination of fuel or air filters, jets or channels. Or maybe the carburetor is just not adjusted correctly.

To eliminate the malfunction, it is necessary to replace or rinse the appropriate filters, blow through all the channels and jets of the carburetor with air under pressure, and make the necessary adjustments.

Leakage Fuel leakage can occur due to a loss of tightness in the fuel tank, filter, pump, carburetor, or multiple fuel line connections.

To eliminate the malfunction, tighten the clamps of the fuel hoses, change the damaged gaskets. Leakage caused by mechanical damage to the elements of the power system is eliminated by replacing them. If you prefer repairs, then it must be done only in specialized workshops.

2.3 Assembly and disassembly work carried out during the repair process

Unscrew the screws securing the carburetor cover and carefully remove it so as not to damage the gasket and float.

Disassembly of the carburetor cover:

· carefully push the axle 1 (fig. 8.) of the float 3 out of the racks with a mandrel and carefully remove it without damaging the tongues of the float;

Remove gasket 4 of the cover, unscrew the needle valve seat 2, unscrew the branch pipe 15 of the fuel supply and remove fuel filter 13;

· unscrew the idle fuel jet housing with the solenoid shut-off valve 10 and remove the jet 9;

· Unscrew the axle 19, remove the air damper control lever 18, disconnect the spring of the air damper control lever. If necessary, turn out the screws of the air damper, remove the damper 14 and axle 16;

· disassemble the diaphragm trigger by removing the cover 8 of the trigger assembly with the adjusting screw 7. Remove the spring 6 and the diaphragm 5 with the stem.

Rice. 8. Carburetor cover disassembled 21051-1107010

Disassemble the carburetor body (Fig. 9.), To do this, perform the following operations:

Rice. 9. Carburetor body disassembled 21051-1107010

· remove cover 3 of accelerator pump with lever 2 and diaphragm 1;

· take out sprayers 10 of the accelerating pump and sprayers 11 of the first and second chambers;

· unscrew the nut of the throttle valve axis of the first chamber, remove the cam 4 of the accelerator pump drive and the washer;

Unscrew the adjusting screw 27 for the amount of idle mixture;

· having broken the plastic plug 23, unscrew the adjusting screw 25 of the quality (composition) of the idle mixture;

· remove the cover 5 of the economizer of power modes, the diaphragm 6 and the spring;

· unscrew the fuel jet 7 of the power mode economizer, the main air jets 12 with emulsion tubes and the main fuel jets 13 of the main metering systems.

Assemble the carburetor in reverse order. When tightening the screws for fastening the throttle valves, emboss the screws along the contour on a special device that excludes deformation of the axes of the dampers.

3. Safe organization of work

In order to prevent an accident, each worker in the production process must be guided by the technological instruction, observe the safety and fire safety rules set forth in this instruction, and the administration is obliged to provide workplaces with everything necessary for safe work and create normal working conditions.

Safety precautions when carrying out vehicle maintenance

Keep the workplace clean and tidy. Cover spilled oil products with clean sand, then remove them and wipe off any traces of liquid. Collect cleaning material in an iron box with a tight lid.

The units to be removed must be thoroughly cleaned and wiped down so that it is convenient to disassemble them.

During operation, it is forbidden to stand on moving wheels and other unstable parts of the machine.

Cylinders and pistons must not be placed on the edge of a table or workbench.

It is forbidden to disassemble or assemble the units in a suspended state.

When dismantling or installing elastic coil springs, special pullers are used to prevent the spring from flying out.

Conclusion

The paper considers the device and principle of operation, features of maintenance, diagnostics and repair, as well as analyzes the main malfunctions, detailing and features of assembly and disassembly of the carburetor engine power system.

Bibliography

1. Kramarenko G.V. Technical operation of cars. M., Avtotransizdat, 1962.

2. S. I. Rumyantsev, A. G. Bodnev, N. G. Boiko, et al.; Car repair. Autotransport textbook. technical schools. Ed. Rumyantsev. - 2nd ed., revised. and additional - M.: Transport, 1988. Borovskikh Yu.I., Buralev Yu.V., Morozov K.A. Car device: A practical guide - M .: Higher school, 1988

K.P. Bykov, T.A. Shlenchik. Car GAZ-21 and its modifications. Service and device

The power system of a carbureted engine includes a fuel tank, fuel lines, fuel filters, a fuel pump, an air filter, a carburetor and an intake manifold. The power system also includes the exhaust pipe of the engine and the muffler.

The supply of fuel for the operation of the engine is stored in a tank, from which fuel is supplied to the carburetor by a pump through the fuel lines. The sediment filter cleans the fuel from mechanical impurities and separates water that accidentally got into it. The air filter cleans the atmospheric air entering the carburetor from dust.

The carburetor prepares a combustible mixture, which enters the cylinders through the intake pipe. The exhaust pipe removes exhaust gases from the cylinders. The muffler reduces the noise of exhaust gases escaping into the atmosphere.

The principle of operation and the general arrangement of the carburetor. The body of the simplest carburetor contains the float and mixing chambers. A float acting on a needle valve maintains a constant fuel level in the float chamber. The hole communicates the float chamber with the atmosphere.

In the upper part of the mixing chamber there is an inlet air pipe, in the middle part there is a diffuser having a narrowed flow area (neck), and in the lower part (outlet pipe) there is a damper, called a throttle, mounted on a roller passed through holes in the walls of the mixing chamber. Using a lever on the outer end of the throttle shaft, the latter can be rotated to the desired position. The outlet pipe of the mixing chamber is connected to the engine inlet pipeline by means of a flange.

The cavity of the float chamber communicates with the atomizer brought into the neck of the diffuser by a jet having a calibrated hole. The upper cut of the atomizer is located above the fuel level in the float chamber, the fuel does not pour out by gravity.

During engine operation, atmospheric air entering the cylinders during the intake strokes passes through the mixing chamber, in which, as in the cylinders, a vacuum is formed equal to the pressure difference between atmospheric and in the mixing chamber. It is known that when a liquid or gas moves through a pipeline, their pressure in the narrowed section decreases, and the speed increases. Therefore, the greatest rarefaction, and consequently, the maximum air velocity is created in the neck of the diffuser

The main malfunctions of the power system gasoline engine with carburetor are:

Stopping the fuel supply to the carburetor;

formation of too poor or rich combustible mixture;

Fuel leakage, difficult starting of a hot or cold engine;

Unstable idling of the engine;

Interruptions in the engine, increased fuel consumption;

· The main reasons for a fuel cut can be: damage to the valves or diaphragm of the fuel pump; filter clogging; freezing of water in fuel lines. In order to determine the reasons for the lack of fuel supply, you need to disconnect the hose that supplies fuel from the pump to the carburetor, lower the end of the hose removed from the carburetor into a transparent container so that gasoline does not get on the engine and it does not ignite, and pump fuel with the fuel pump manual priming lever or cranking the crankshaft with a starter. If at the same time a jet of fuel with good pressure appears, then the pump is working.

· Then you need to remove the fuel inlet filter and check if it is clogged. Pump failure is indicated by poor fuel supply, intermittent fuel supply, and no fuel supply. These reasons may also indicate that the fuel supply line from the fuel tank to the fuel pump is clogged.

· The main reasons for the depletion of the combustible mixture can be: decrease in fuel level in the float chamber; sticking of the needle valve of the float chamber; low fuel pump pressure; fuel jet contamination.

· If the capacity of the main fuel jets changes, this leads to an increase in the toxicity of exhaust gases and a decrease in the economic performance of the engine.

· If the engine loses power,“shots” are heard from the carburetor, and the engine overheats, then the causes of these problems may be: poor fuel supply to the float chamber, clogging of jets and sprayers; clogging or damage to the economizer valve, air leakage through leaks in the carburetor mounting and intake manifold. The loss of engine power when running on a lean mixture can occur due to the slow combustion of the mixture and, as a result, less gas pressure in the cylinder. When the combustible mixture is depleted, the engine overheats, because the combustion of the mixture occurs slowly and not only in the combustion chamber, but throughout the entire volume of the cylinder. In this case, the heating area of ​​the walls increases and the temperature of the coolant rises.

To repair and eliminate defects, it is necessary to check the fuel supply. If the fuel supply is normal, it is necessary to check if there is air leakage in the connections, for which the engine is started, the air damper is closed, the ignition is turned off and the carburetor and intake pipe connections are inspected. If wet spots of fuel appear, this indicates the presence of leaks in these places. Eliminate defects by tightening nuts and bolts. In the absence of air leakage, check the fuel level in the float chamber and, if necessary, adjust it. If the jets are clogged, they are blown out with compressed air or, in extreme cases, carefully cleaned with soft copper wire.

Fuel leak should be removed immediately due to the possibility of fire and excessive fuel consumption. It is necessary to check the tightness of the drain plug of the fuel tank, the connections of the fuel wires, the integrity of the fuel lines, the tightness of the diaphragms and the connections of the fuel pump.

The reasons for the difficult start of a cold engine may be: lack of fuel supply to the carburetor; malfunction of the carburetor starting device; ignition system malfunctions.

If fuel is well supplied to the carburetor and the ignition system is working, a possible cause may be a violation of the adjustment of the position of the air and throttle valves of the primary chamber, as well as the pneumatic corrector of the starting device. It is necessary to adjust the position of the air damper by adjusting its cable drive and check the operation of the pneumatic corrector.

Unstable engine operation or the termination of its operation at a low idle speed of the crankshaft may be caused by the following reasons: incorrect ignition setting; the formation of carbon deposits on the electrodes of the candles or an increase in the gap between them; violation of the adjustment of the gaps between the rocker arms and camshaft cams; reduction in compression; air suction through the gaskets between the head and the intake pipe and between the exhaust pipe and the carburetor.

First you need to make sure that the ignition system and the gas distribution mechanism are working, then check the absence of sticking of the throttle valves and their drive, adjust the carburetor idle system. If the adjustment does not help to achieve stable engine operation, it is necessary to check the cleanliness of the jets and channels of the carburetor idle system, the serviceability of the forced idle economizer, the tightness of the connections of the vacuum hoses of the EPXX system and the vacuum brake booster.

After every 15,000–20,000 km of run, check and tighten the bolts and nuts securing the air cleaner to the carburetor, the fuel pump to the cylinder block, the carburetor to the intake piping, the intake and exhaust piping to the cylinder head, the silencer exhaust pipe to the exhaust piping, the silencer to the body . Remove the cover, take out the air cleaner filter element, replace it with a new one. When working in dusty conditions, the filter element is changed after a run of 7000–10,000 km, the fine fuel filter is changed. When installing a new filter, the arrow on its housing must be directed in the direction of fuel movement to the fuel pump. It is necessary to remove the cover of the fuel pump housing, remove the strainer, rinse it and the cavity of the pump housing with gasoline, blow through the valves with compressed air and install all the parts in place, unscrew the plug from the carburetor cover, remove the strainer, rinse it with gasoline, blow it with compressed air and put it on place.

In addition to the above works, after 20,000–25,000 km of run, the carburetor is cleaned and its operation is checked, for which the cover is removed and contaminants are removed from the float chamber. Pollution is sucked out with a rubber bulb along with fuel.

Then the jets and carburetor channels are blown with compressed air; check and adjust the fuel level in the carburetor float chamber; check the operation of the EPXX system; adjust the carburetor to match the content of carbon monoxide CO and hydrocarbons in the exhaust gases of cars with gasoline engines.

Maintenance of the fuel system also includes a daily inspection of the connections of the fuel lines, carburetor and fuel pump to make sure there are no fuel leaks. Warming up the engine, you need to make sure that the engine is stable at a low crankshaft speed. To do this, the throttle valves are quickly opened, then they are abruptly closed.

Fuel pump repair.

Insufficient filling of the carburetor with fuel can be caused by a malfunction of the fuel pump. In this case, the pump is disassembled, all parts are washed in gasoline or kerosene and carefully inspected to identify cracks and breaks in the housings, leaks in the suction and discharge valves, turning in seats or axial displacement of the nozzles of the upper casing, ruptures, delamination and hardening of the pump membrane, elongation of the edges of the hole for the membrane thrust. The hand drive lever and lever spring should work well. The pump filter must be clean, the mesh must be intact and the sealing lip must be even. The elasticity of the spring is checked under load. Springs and diaphragms that do not meet technical requirements, are to be replaced.

In the fuel pump housing, there may be such damage as wear of the holes for the axis of the drive lever, thread breaks for the cover fastening screws, warping of the cover and housing split planes. Worn holes for the axis of the drive lever are expanded to a larger diameter and a bushing is inserted; Stripped threads in holes can be repaired by cutting larger threads.

Warping of the contact plane of the lid is eliminated by rubbing on the plate with paste or sandpaper.

Carburetor repair.

To repair a carburetor, it is usually removed from the car, disassembled, cleaned and its parts and valves blown with compressed air; change worn out and failed parts, assemble the carburetor, adjust the fuel level in the float chamber and adjust the idle system. It is possible to remove and install the carburetor, as well as fasten and tighten the fastening nuts only on a cold carburetor, with a cold engine.

To remove the carburetor, you must first remove the air pump, then disconnect the cable and return spring, rod and shell of the air damper drive rod from the throttle control sector. Next, unscrew the fastening screw and remove the carburetor heating unit; then disconnect the electrical wires of the carburetor limit switch, and in some cars, the forced idle economizer. After that, the carburetor fastening nuts are unscrewed, removed and the intake pipe inlet is closed with plugs. Install the carburetor in reverse order.

In order to disassemble the carburetor cover, you need to carefully push the axis of the floats out of the racks with a mandrel and remove them; remove the cover gasket, unscrew the needle valve seat, fuel-fuel feed line and remove the fuel filter. Then unscrew the actuator of the idle system and remove the fuel jet of the actuator; unscrew the bolt and remove the liquid chamber; remove the spring housing clamp, the spring itself and its screen. If necessary, disconnect the body of the semi-automatic starting device, its cover, diaphragm, plunger stop, throttle opening adjusting screw, throttle lever pull rod.

In some cases, it is possible to restore the carburetor's performance without removing it from the car and without completely disassembling it, but by adjusting the idle system, air damper drive, turning out and cleaning its filter, or partially disassembling the carburetor.

Partial disassembly includes removing the cover, adjusting the fuel level in the float chamber and purging the jets.