JPS5818552A - Unit injector - Google Patents

Abstract

PURPOSE:To adopt a reverse reed plunger, variable with injection timing, and change opening pressure of a valve to be higher in accordance with an injection quantity especially at a small injection quantity, in an injector controlled with operation through a tappet. CONSTITUTION:A tappet 7 is moved by a cam 6a, driven in accordance with speed of an engine, and operation of the tappet 7 causes a plunger 4 in a plunger barrel 5 to move shuttling, then fuel is injected from an injection nozzle 3. A reverse reed 4a is formed to the head part of said plunger 4. This reverse reed 4a is formed in such a manner with injection start timing variable and injection end timing constant. Further the plunger 4 is constituted in such a manner that a spring receiver 10 is provided to its lower end and the displacement of the plunger 4 is transmitted to a nozzle spring 9, pressing a needle valve 2, through this spring receiver 10. In this way, opening pressure of the needle valve 2 can be changed to be higher suitably to an injection quantity in accordance with decrease of the injection quantity.

Description

Detailed Description of the Invention This IJI consists of an injection nozzle that carries a needle valve, a nozzle spring that presses the needle valve, a plunger barrel in which a plunger is fitted in a rotating and slidable manner, and a machine II fighting speed [ It is used in internal combustion engines, especially diesel engines, and has a tappet that is driven by a camshaft that is driven in accordance with K, and the plunger reciprocates due to the operation of the tappet, injecting fuel with an injection nozzle. This invention relates to improvements to enit injectors.

In a normal diesel engine fuel injection system, the fuel injection
The Sotto injection valve is a relatively long injection pipe that is covered with fireworks.
After the fuel is pumped by the plunger of the injection pump, it passes through the injection pipe and is injected from the injection valve. Therefore, since the OJE fuel sent from the plunger is affected by the volume of the injection pipe OIIS, it is impossible to completely control the injection rate by injection 9PK by the plunger oil feed rate. For example, even if the fuel delivery period by the plunger is the same depending on the cam angle, the actual injection period may become longer as the rotation speed increases, or the control of the injection amount in the small injection amount region may be caused by rotation. The ninth step to solving these problems, even if you live in the odor
Various unit injectors have been proposed in which an injection pump and an injection valve are integrated and an injection pipe is omitted.

As with the normal injection II system, in such a unit injector, the injection pressure is constant because the injection amount is small during fuel injection at low load, and the atomization of the injected fuel is reduced. There are nine drawbacks that make it worse. This is a butterfly! Kll sound and exhaust gas countermeasures, and even 11! Good tuning performance! For this reason, conventional methods have been used to raise the opening pressure of the injection valves overall to increase the injection rate and promote atomization and mold formation of the fuel.

However, even in this case, if the valve opening pressure is constant, abnormal injections such as secondary injection and asymmetric injection will occur, resulting in inconveniences such as car knock and engine hunting.

The present invention provides the unit injector described above.
In addition to adopting a reverse reed sylanger for the plunger that allows variable injection start timing, the nozzle spring is configured to be suppressed by each plunger's pressure stroke, especially when the injection amount is small. The valve opening pressure is changed in accordance with the injection amount so that the pressure increases, and this completely eliminates the above-mentioned disadvantages.

, then illustrate this inventiongI71) If! I will be explained.

The injector body is a plunger barrel into which the injection nozzle spring gear that supports the needle valve is rotatably and slidably fitted! , and a tappet 7 driven by the cam taK of the camshaft 4 which is driven in accordance with the engine rotational speed 1iK are sequentially assembled. The injection nozzle J is a space 11 through which the injected fuel passes.
7a, shouldering the fuel reservoir Jb and the nozzle hole JC of Wa@, between the nozzle J and the plunger barrel there is a through hole jl through which the communication path JaK of the nozzle J passes, and a hII row holder through which the needle valve J passes. A spacer is interposed. One end of the nozzle spring that suppresses the needle valve 2 is a spring receiver i.

There is a support field in the hole 1, but this holder 10 has a hole 1 concentric with the needle valve 1.
0m, and the rod/JK fitted through the K11llll receiving member // in this hole IOa plunges.
It is supported by the YII Department. The bearing member /l can be a Zeel pairing, and is provided so that frictional force is not generated between the plunger and the shaft holder 10 when the plunger moves and is pulled. The rond l is always in contact with the direction of the syringe I11 by the spring blade of the nozzle springer, and the displacement of the syringe 11 is transmitted to the nozzle springer via the spring holder 10f. Therefore, the nozzle springer is pressed during the pressure stroke of the plunger, thereby pushing the needle valve λ to increase the valve opening pressure.

This four-piece may be integrated with the plunger and spring holder IO, and the plunger barrel and the injector body's fuel reservoir and delayed overflow hole! 1 is formed, and the fuel reservoir J)/aK is always filled with fuel from a fuel tank (not shown). This fuel is barreled during the intake stroke of the plunger≠! The overflow hole! From 1, the spring depth of the barrel I in which the nozzle springer forming the plunger chamber is housed! KI in b is set to enter. The so-called reverse lead 44m is formed in the I[lIe'C of the Siranjar, so that the injection start timing is variable and the injection trailing timing is constant. This plunger is located at the brim @$b at the base end of the plunger spring/J.
It is supported in the hole of the tappet 7 by a spring holder that receives mt. Siranja Spring/J (Q and others1ilI!
It is supported by a spring receiver 11 attached to the injector main body/KIIL. The plunger barrel IK has a notch that engages with the boxwood S and G of the syringe, and a control sleeve 14 is rotatably fitted therein. Connected lever/4bfp.

The operation of the unit injector constructed as described above and based on the nine outputs will be explained.

6 from the fuel tank in the fuel ttitvia as described above.
The fuel flows through the overflow hole of the plunger barrel I during the intake stroke of the plunger! Spring through the breath! jb. When the tappet 7 moves downward 111 times at t-111/II inside the main body against the nozzle spring due to the rotation of the camshaft 4, the plunger moves as shown in Figure (1). barrel! The fuel pressure feed 1 is started by the reverse lead 4I of the plunger membrane blocking the overflow hole Za of the barrel 1. This displacement of the plunger 3 is transmitted through the rod /J and spring 9/Of to the nozzle spring y/PK%, so the nozzle spring y/PK% moves as the plunger 9 moves downward. As shown in (2), the opening pressure of the needle valve is t compared to the opening pressure set by the normal nozzle springer until the plunger reaches the top dead center. It increases gradually. When a large amount of injection is required, such as during high load, move the fuel control rack to the fuel increase direction and control sleeve 14t Leno? -/4bt
- Rotates through S, thereby causing the piston S to rotate; the plunger engaging with the control sleeve 14 also rotates; ! The timing of closing the fuel cell, that is, the timing of starting injection, becomes earlier, and the amount of injection increases accordingly. Therefore, due to this increase in the injection amount, the injection pressure %a% (in other words, the needle 4J becomes the λ-(i)
The engine will immediately turn back to zero and perform fuel injection.

On the other hand, at low speeds and low loads, the control rack moves in the direction of fuel reduction due to the action of Ganona.

The control sleeve 14 rotates the plunger # in the opposite direction to the high load situation. Reversing at 9L - The time when Hatake blocks the overflow hole 7m is delayed, and the injection start time is delayed as shown in 41, and the injection amount is slightly reduced accordingly. Figure lI2 To explain (2), since the Kll valve pressure is increasing with the stroke of the plunger, the needle 5 is increased based on the increased valve opening pressure P during the rising process.
F-2 @ J 1iil (@) It gets hot because the valve opens and injects.

According to this invention, 1. In the a-nit injector, as the injection amount decreases, the needle valve WIA9P
In order to increase the pressure, it is possible to change the valve opening pressure depending on the injection amount, increase the injection rate at low continuous low loads, and improve the fuel efficiency. As a result, it not only eliminates the occurrence of car knock, but also improves the fuel consumption rate while purifying the exhaust gas, and the 119th is especially reversed. At low loads, in addition to the high valve opening pressure, the start of injection is delayed, which improves the atomization of the injected fuel and reduces ignition delay (1%), which is extremely effective in reducing resources at idle. Since the injection end timing is constant and 9 fuel injections can be performed, it is possible to have the function of a four-domain timer.Furthermore, from between the Kll formation needle valve and the injection nozzle, the glue oil can be injected. Towing guided into the spring chamber of plunger 2rel, w
It is possible to omit the nine-tap pipe, which is essential in the production of rice, and it is possible to simplify the process.

[Brief explanation of the drawing]

The first one is 69.69. Figure 2 shows its working theory @ll1il. K...Needle valve, J, Injection nozzle, 3-plunger, 3-reverse lead,! ...Plunger barrel! ,,,
Cam shaft, 4■...Cam%7-tappet, day nozzle spring, lO...spring holder.

Claims (1)

[Claims] The injection nozzle on the needle valve T-shoulder, the nozzle spring that presses the needle valve, the plunger is rotated and slidably engaged with the nine-piece parallel, and the engine [I series [K] is driven according to the force of the five-axis cam. In the KL7 knit injector, the injection start timing is made variable on the head 11 of the plunger in order to inject fuel from the injection nozzle by reciprocating the f ranger by the tappet t) actuated by the tappet 111. In addition to providing a reverse lead, a spring holder that receives one end of the nozzle spring O is connected to the plunger head, and when the nozzle spring is pressed by the plunger force 1 of 4I times, the M valve pressure of the P needle valve is controlled. An engineered knit injector characterized by a raised K.