Here you can get how to fuel pipes checking. Here we provides to A typical fuel system, Replacing connectors and Fuel Systems Working Principle ect.
Any fuel leak, however small, can cause a fire. Do not drive a car with a suspected leak until you have cured it. Never leave a car dripping petrol where a passer-by may throw a cigarette end under it. A small fire extinguisher, fitted where you can get at it quickly, is a valuable accessory.
A typical fuel system
Whenever you check fuel pipes, disconnect the battery to stop stray sparks igniting petrol or petrol vapour. Above all, put out all naked lights and cigarettes. Use a torch instead of an inspection lamp, which could start a fireplace if the bulb is accidentally broken. The fuel pipe of a car with the engine in front and the fuel tank at the rear generally runs under the floor, where it are often exposed to corrosion and knocks. For most of its length it’s usually made from metal, but different materials are used on different sections and these are linked with various sorts of connectors. Sometimes the whole pipe is plastic.
Sometimes there’s a twin piping system, with supply and return pipes. The fuel pump circulates petrol in an endless loop, from the tank and back again, from which the carburettor draws off the maximum amount because it needs. A normal, single fuel pipe begins at the outlet on top or at the side of the tank, where it’s usually combined with the electrical fuel-tank sender unit which operates the fuel gauge. There is a brief pick-up pipe with a filter reaching into rock bottom of the tank.
From the outlet the pipe runs to the fuel pump – either a mechanical one mounted on the engine , or an electrical one which is usually sited at the rear next to the tank, or submerged in it. The pump sends the fuel to the carburettor , but there are one or more filters on the way – often in unsuspected places that are difficult to reach. The last a part of the fuel pipe, inside the engine compartment, has got to be flexible to permit for the engine moving on its rubber mountings.
The flexible section of the piping is usually made of reinforced rubber hose , but sometimes clear, flexible plastic tube is used. The most usual type of connector for metal fuel pipes on modern cars is a short length of rubber hose fitting over the pipe ends and secured by two hose clips. Sometimes there are no clips, and the connector is a push-on fit.
On some earlier cars rigid joints are used on metal piping, especially where it’s attached to the tank outlet. A tube nut fits over the pipe and is screwed tight to force the pipe against an ‘olive’ – a piece of soft metal shaped sort of a hollow bead. The ends of the olive are squashed to form a fuel-tight joint. Sometimes there’s no olive, and therefore the tube nut forces the ends of the tube on to a tapered seating which spreads out the end of the tube into a bell.
Leaks are often caused by corrosion in steel pipes, and cracks and abrasion in all types. The clips holding the pipe to the chassis may damage it, or they’ll rust and fall off in order that the pipe becomes loose. It .may then get dangerously on the brink of the pipe. The pipe can also be damaged by stones on unmade roads, or maybe by jacking the car up with the jack within the wrong place.
Apart from damage to the pipe itself, joints may come loose and leak. Rubber joints may fray, or the clips loosen. Metal joints tend to leak once they are pulled or pushed, in order that the olive or expanded pipe end is distorted and not forms an efficient seal with its connector. Inspect all of them carefully at regular service intervals.
If you can smell petrol
The first sign of a leak is usually a strong smell of petrol. If you smell petrol at any time except once you have just filled the tank, or once you have difficulty starting the car and have flooded the carburettor, suspect a leak and look for it. If there’s petrol under the car after filling the tank, check the flexible hose between the filler neck and therefore the tank neck. A split within the hose will leak petrol because it is being pumped in.
Other evidence could also be a humid patch or stain under the car. Where petrol has run down a part of the car from a leak then dried, it leaves a whitish, chalky mark. just because the mark is dry, don’t suppose that the leak has stopped. Leaks may occur only at certain times, for example only when the tank is full or the car is tilted during a certain direction.
The carburettor is that the commonest source of leaks, so start looking there. The fault might be the carburettor flooding , instead of a leak. Look at the joint between the gas line and therefore the carburettor, then check other joints, working all the way back to the tank. Put the car abreast of ramps or axle stands to examine the section under the ground . Bend flexible pipes between your fingers to point out up splits or cracks. Push clips and metal joints to ascertain if they’re loose.
Feel around joints to ascertain if they’re wet, petrol may line a pipe before it begins to drip, which may be misleading. Once you’ve got found the leak you’ll make a short lived repair, but anything that’s damaged should get replaced completely as soon as possible. If a plastic line is broken the entire line must be replaced, since improvised joints won’t remain leakproof for long. Certain petrol blends sold in Europe could cause plastic fuel lines to expand or swell. Sagging fuel pipes are the primary sign that this is often happening. confirm the pipes are securely clipped on.
Replacing connectors
Rubber connectors are often damaged by being removed within the wrong way. If they’re pulled straight off, the strain makes them become narrower and tighter, and that they may tear. They should be twisted off. This also applies to longer lengths of rubber hose. Pushing on a connector or hose is seldom a drag , but don’t use a lubricant to ease it or jointing compound to seal it. this applies to all or any sorts of connector used on fuel pipes.
Make sure any clips are correctly positioned. don’t overtighten them, particularly once they are wire clips, for these can cut through a hose. When a metal connector needs replacing, the pipe is usually damaged also as the connector. If there’s enough pipe, you’ll stop the damaged section. With the sort of connector that relies on an expanded or ‘belled’ endways the pipe, you want to bell the top before screwing up the nut tightening the nut completes the belling and forms the seal.
Strictly this could be through with a special belling tool, but in an emergency you’ll usually manage it by sticking a pair of long-nosed pliers into the top and twisting them round to expand the top into a bell. If you’re using a new nut, slide it over the top of the pipe before you begin to bell the top , or it’ll not continue . Have the joint sealed with a correct belling tool as soon as possible.
Fitting a metal pipe
A new metal fuel pipe is typically supplied straight and unshaped. it’s easy to bend – but also easy to kink. If the old pipe remains in one piece and undistorted, take it off to use as a pattern for the new one. Make gentle bends and curves by bending the new pipe carefully together with your hands. Check frequently that it matches the old pipe and fits the space. Make tight bends round a tube a minimum of 2 in. (50 mm) in diameter. If you re-route the new pipe, keep it faraway from the exhaust, moving parts of the suspension or handbrake mechanism, jacking points and other exposed places.
Fixed-jet Carburettor
The fixed-jet carburettor resembles the simpler variable-jet type (See How variable-jet carburettors work ) in having a venturi – a constricted neck – through which air flows on its way to the engine .
The partial vacuum caused by increased air speed through the venturi sucks fuel through a jet to mix with the air.
Similarly, air flow is controlled by a throttle flap linked to the accelerator pedal, to regulate engine speed.
Above the throttle a choke flap partially blocks the air flow, to give a richer mixture for starting. As in all carburettors , a float chamber provides a steady supply of fuel.
Fuel Systems
Internal combustion engines require fuel in order to run and motor vehicles are thus equipped with a fuel system that keeps the engine supplied with the correct amount of fuel, for all operating circumstances.
The function of the fuel system is to store and supply fuel to the cylinder chamber where it can be mixed with air, vaporized, and burned to produce energy. The fuel, which can be either gasoline or diesel is stored in a fuel tank. A fuel pump draws the fuel from the tank through fuel lines and delivers it through a fuel filter to either a carburetor or fuel injector, then delivered to the cylinder chamber for combustion.
Components of Fuel System
The main components of the fuel system consist of fuel tank, pump, filter and injector/carburetor.
Fuel Tank: It acts because the reservoir for the vehicle’s fuel. The tank has an electronic “trigger” that conveys statistics regarding the quantity of gasoline to the fueloline gauge.
Fuel Pump: Its number one feature is to draw fuel from the gasoline tank and pump it into the inner combustion engine. There are sorts of fuel pumps: mechanical and electric, which are utilized in motors with carburetors and electronic gasoline injectors, respectively.
Fuel Filter: It is constant in both the ends of the gasoline pumps to split impurities from the gasoline, thereby ensuring most beneficial engine performance.
Fuel Injector: It is an electronic valve that opens/closes at normal periods to supply the proper quantity of gasoline to the engine.
Carburetor: Its principal cause is to combine the proper quantity of air and gasoline and supply it to the engine. The carburetor is the predecessor of the gasoline injector.
Working Principle
Some of this may seem a little silly, as many components are pretty obvious to all of us. Fundamentally, once you fill the tank with gas the device is “ready.” When you begin the automobile the gasoline pump begins the method of drawing gasoline from the gasoline tank, thru the gasoline strains and gasoline clear out out, to the device that controls gasoline/air shipping to the engine (a carburetor or gasoline injector). While the automobile is going for walks a non-stop deliver of gasoline is added on this fashion.
The fuel system in current automobiles is a complicated and intricate combination of components and electronics. Generally, Fuel systems work in the
following ways:
• Fuel is delivered from the gasoline tank to the fuel injectors thru a gasoline pump and fuel lines. The pump is typically placed near the gasoline tank or inside the tank itself.
• Fuel leaving the gasoline tank and gasoline pump passes thru a gasoline clear out out which purifies and receives rid of any containment. This is typically a excessive capability inline design, to maximize go with the drift prices.
• Fuel travels alongside the fuel lines and is delivered to the fuel injectors. Fuel Injector pressures are controlled thru a pressure regulator.
• Any gasoline which isn’t used and exceeds pressure rates is returned via fuel strains back into the fuel tank.
