The Working Principle of Diesel Fuel Injection Pump

by MOU YONG HONG on December 01, 2021

The fuel injection system pump is the heart of the diesel. Precisely delivered fuel maintains a rhythm or timing that keeps the engine running smoothly. Simultaneously, the pump also controls the quantity of fuel needed to realize the specified power. The injection pump does the work of both the throttle and therefore the ignition needed in gasoline engines. When troubleshooting an internal-combustion engine, you check compression, fuel, and spark. Diesel doesn't have an ignition, so there's one less thing to travel wrong with it. Major advances within the development of the diesel are immediate results of a better fuel injection system. Here is how the injection pump works.

Inline-injection (Jerk) Pumps

The first pumps to use plungers to force metered fuel to the combustion chamber were developed back within the 1890s. It took almost forty years, but in 1927 Bosch introduced the mass-produced helix-controlled inline pump. These first pumps look tons just like the Bosch P7100 (P-pump) on '94 to '98 Dodge Ram 5.9L Cummins engines. Sometimes called jerk pumps, they're constructed from separate pump and plunger units connected inline, one per cylinder. they're activated by a cam, which is mechanically connected to the engine. Still, the pump has the power to vary the timing, although to not the sophistication of an electronically controlled system. Inline injection pumps appear as if mini inline engines. The earliest inline injection pump delivered 3,000-5,000 psi of injection pressure, while the newer Bosch P7100, found on '94 to '981/2 Cummins engines, delivers 18,000 psi of pressure.

Distributor (Rotary) Injection Pump

These sorts of pumps have just one fuel-metering plunger. A spinning rotor makes a hydraulic reference to the various ports on the distributor's head, somewhat almost like the way a distributor works on an internal-combustion engine. The advantages of a rotary-style pump with just one plunger are all the shots of fuel are precisely the same, and it makes for a smaller overall package. Also, distributor-style pumps have less moving parts compared to inline pumps. Two samples of mechanical rotary pumps are the Stanadyne DB2 and therefore the Bosch VE. The Stanadyne DB2 produces 6,700 psi of pressure, while the Bosch VE produces 17,000 psi.

An example of an electronic rotary pump is that the Bosch VP44, which is in a position to supply 23,000 psi of pressure. This is often the neatest pump with the foremost responsibility-even compared to new common-rail CP3 pumps. This is often the case because all a CP3 must do is create pressure. Besides creating pressure, the VP44 must electronically control the timing and quantity of fuel delivered to the engine.

Common-Rail Injection

With a common-rail fuel injection system, the pump itself lost much of its authority to form a choice when the fuel it pressurizes gets delivered and at what quantity. As an example, the CP3 pump receives fuel from the fuel tank. It then uses a radial-piston design to increase pressure immensely. The highly pressurized fuel is shipped to the common-rail which is actually an accumulator for the injectors. The injectors take over from there.

Unit injectors

The lines connecting the injection pump to the fuel injector produced problems for early diesel engineers. So in 1905, Carl Weidman got obviate them by combing the injection pump and thus the injector. The unit injector could also be a compact fuel injection system design during which the pump plunger creates high by a mechanical force applied by the engine. The plunger and injector blend into one unit whose job is to deliver the fuel spray to the combustion chamber. the foremost common application for unit injectors are Volkswagens and massive diesel engines. 

Interesting fuel injection system Facts

*The first diesel engines used gas to blast fuel into the combustion chamber. This was leftover technology from experiments with coal dust.

*The Atlas Imperial Diesel Company of Oakland, California, developed its first common-rail equipment back in 1919.

*A major problem for the fuel injection system isn't getting a dribble at the highest of the injection. Even a touch extra drip would throw off the combustion cycle.

*In today's diesel engines, fuel leaves the injector at 30,000 psi. For comparison, this number fits within the range of pressures during which waterjets operate. Waterjet uses highly pressurized H20 to cut through many different kinds of materials, including plastic, wood, steel, and aluminum.

*Cummins and Scania teamed up to form the XPI High-Pressure Common-rail injection system, which is during a position to require care of high fuel pressure at any engine speed.

*The first injection pumps had oil dipsticks.


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