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Now the car engine, the fuel pump assembly is usually caused by injection pump, governor and other components installed together to form a whole. One governor is to protect the low-speed diesel engine operation and the maximum speed limit, ensure that the injection volume and speed to maintain a certain relationship between the components. The diesel engine fuel injection pump is the most important parts, diesel engines is considered the "heart" part, it will make the engine work once the problem disorders. The following details only fuel pump.
Classification
There inline fuel injection pump, distribution type, monomer type and other three categories, regardless of what type, fuel injection pump is the key to a "pump" is used. The number of pump oil, pressure and time must be very precise, and automatically adjust according to load. Injection pump is a precision machining, manufacturing process of complex parts, usually at home and abroad by injection pump of diesel engine cars in the world produced a few specialized plants.
In-line fuel injection pumps for an example see "pump" is how it works:
Pump power source can be run, it lower the camshaft is driven by the engine crankshaft gear.
The key part is the fuel pump plunger, the syringe if the hospital common metaphor, it is called movable plunger stopper, syringe plunger on the known sets of assumptions in the cylinder is installed inside a spring withstand column Plug one end of the plunger contacts the other end of cam shaft, camshaft rotation when the week, the plunger comprising a plunger will move up and down in time, this is the basic fuel injection pump plunger movement means.
Plunger and the plunger is processing a very sophisticated set of accessories. Plunger body has an inclined groove, the plunger put on a small hole called the intake, this intake is full of diesel, when the piston groove tilt against intake, the diesel fuel into the plunger comprising a plunger is camshaft top to a certain height, tilt the plunger and the suction slot staggered intake is closed, so that diesel can not breathe and can not be pressure from the plunger when the pressure continued to increase diesel fuel, diesel oil pressure to a certain extent it will open a one-way top surging out into the injector valve and then into the cylinder combustion chamber from the nozzle.
Here in particular to point out that diesel engines are into the pipeline and the return pipe, tubing into easy to understand, then the return pipe what is the use? Each piston had a certain amount of diesel exhaust is only part of the spray into the cylinder, and the rest go by the back vent hole and used to go back to change vent to regulate the fuel injection quantity of fuel.
When the piston up to the "on the spot" down after the move, tilt piston intake slot will meet with the diesel has been sucked into the plunger sleeve inside, repeat the above action. Inline fuel injection pump plunger system, each group corresponds to a cylinder, four cylinder piston systems have 4 groups, the relatively large size, more and more used in medium-sized car. Such as buses and large trucks on the general use of inline fuel injection pump diesel engines.
Car and light vehicle diesel engine fuel injection pump is usually assigned type, small size, light weight, fewer parts and simple structure. It uses two plunger system (or a plunger system) pressure, diesel oil into each injector.
Its basic principle is to pump the plunger inside two of the home installed in impeller, the impeller driven by the engine rotation, the plunger also will rotate, due to the raised part of the pressure ring cam moving plunger to plunger play the same role as the pump impeller central to the delivery hole pressure to send diesel fuel, then send out a distributor of diesel filled the entrance, and then press the cylinder in order of injection.
As the two plunger system (or a plunger system) and Movement Speed increased in proportion to the number of cylinders, so this kind of injection pump by the cylinder and the highest number of speed restrictions.
With the development of diesel technology, and now forms the emergence of a single type fuel injection pump (known as single pump or pump nozzle), it is actually the above two types of fuel injection pump, "decentralized", each engine cylinder fuel injection by the respective independent injection units (unit pump or pump nozzle) to complete.
For the single pump, the fuel injection pump and nozzle with a very short between the high-pressure tubing connected to, and for the pump nozzle, the fuel injection pump and nozzle combination as a whole, directly installed in the engine cylinder head, from top camshaft drive home. Their biggest advantage is the ability to reduce or eliminate the flow of diesel and jet process, formed in the high-pressure tubing to the pressure wave effect. Because of this pressure wave will hinder the fuel injection system and the load, speed of a good match, and will increase with the length of high-pressure pipe increases.
Therefore, shortening the length of high-pressure tubing (fuel injection pump of the design) or simply not high-pressure tubing (pump nozzle design) to reduce the pressure between the plunger and the nozzle volume, can be close to the cam contour required for oil law. Especially the pump nozzle, as early as ten years ago has been applied in General Motors, now have precise control of electronic technology, to enhance the performance