KR940000691Y1 - Timer of fuel injection pump for diesel engine - Google Patents

Abstract

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Description

Timer device for fuel injection pump for diesel engine

1 is a structural diagram of a fuel injection pump for a diesel engine.

2 is a cross-sectional view showing the operating state of the timer device of the present invention.

3 is a structural diagram of a conventional timer.

4 is a diagram showing advance curves of various timer devices.

* Explanation of symbols for main parts of the drawings

1a: Left half piston 1b: Right half piston

2a: timer spring 2b: piston spring

3: pin 4: orifice

5: low pressure chamber 6: through hole

7: high pressure room 8: space part

9: piston housing 34: roller holder

The present invention relates to a timer device of a fuel injection pump for a diesel engine.

In general, the injection timing of the fuel injection pump (VE type) for a diesel engine is made so that the injection timing is constantly advanced as the number of engine revolutions increases, as indicated by a dotted line in FIG. 4. As Al, A2, and the advance in the medium and high speed rotation speed increases, the present invention has been completed by contemplating that the engine power and torque can be improved even within the limited soot emission limit.

1 shows a conventional dispensing type injection pump structure, in which the dispensing type injection pump is driven by a drive shaft 41. The rotational force of the drive shaft operates the fuel supply pump 42 to pump from the fuel tank 43. The fuel is injected into the housing at high pressure by the plunger 44 which rotates and reciprocates.

On the other hand, the operation of the governor is to use the centrifugal force of the flyweights 45 in accordance with the change in the rotational speed of the fuel supply pump 42, it is supported by the flyweight holder 47 rotated by the interlocking gear 46 connected to the drive shaft As the flyweights 45 are opened in the direction of arrow I by centrifugal force, one end of the flyweights 45 is pushed in the direction of arrow II, the sleeve 48 being fitted into the inner groove of the flyweights 45. When the starter lever 49 is pushed by the sleeve 48, the corrector lever 50 is pushed in the same direction. Accordingly, the control sleeve 51 opens the hop inlet of the plunger 44, thereby rotating the engine. And it is to control the supply amount of fuel automatically in accordance with the change of the load.

In addition, the fuel which flows into the housing by the fuel supply pump 42 and maintains a constant injection pressure causes the cam disk 52 to reciprocate at the same time as the roller 53 rotates and the plunger 44. Is operated at the same time and the fuel is introduced and discharged, so that the fuel is injected into the combustion chamber of the engine through the discharge valve 54 and the injection nozzle, in which the roller 53 is the cam disk 52 by the timer device 55. In the conventional timer device, as shown in FIG. 3, a timer driver including a timer piston 31, a timer spring 32, and the like is connected to the roller holder 34 using a pin 33. When the high pressure in the pump chamber pushes the timer piston 31 to overcome the force of the timer spring 32 and moves it, the pin 33 rotates the roller holder 34 as much as the movement amount, so that the roller 53 Move the cam disk 52 In this case, the timer device 55 in the fuel injection device for the diesel engine that performs such a function advances the injection timing to adjust the injection timing of the fuel to the engine speed as the engine speed increases. This is a device to correct the injection lag and the ignition lag.

The present invention has such a relationship between the advance amount and the engine speed as indicated by the dotted line in Fig. 4, but the diesel engine has the advance angles such as Al, A2, and B as well as the constant advance. Timer advance is required, and it is very rare in current diesel engines to show rapid advance at low speed and slow advance at high speed like B. However, in this case, it can be easily made by using two-stage spring. Slow progress at low speed, as in the case, if the rapid advance at high speed is thought to be able to improve the performance of the current diesel engine to complete the present invention.

2 is a view showing a timer device and an operation thereof according to an embodiment of the present invention, the roller holder assembly 11 having a roller 53 supported by the roller holder 34 and affixed to the drive shaft 41 of the injection pump. In installing the timer driver 12 to be connected to the pin 3, the timer driver is formed at the tip of the piston housing 9 which extends the opening 5 'at the tip. (3) is formed to support the piston spring (2b) in the rear end to be condensed to one end of the (3), and built in the left half piston (1a) having the insertion space of the timer spring (2a) at the front end and elasticity by the timer spring (2a) In the high pressure chamber 7 formed in the rear end of the piston housing 9, the right and left pistons 1b formed with the supporting projections of the piston springs 2b are provided at the front end and these left and right pistons are installed. Piston spring 2b in space 8 between (1a) and (1b) The spring is made to elastically install the right barn piston 1b by the spring, and the right barn piston is provided with a communication part 10 connected to the pump chamber of the injection pump, and the communication part 10 and the high pressure chamber are formed. The orifice 4 is drilled through (7), the pin (3) is penetrated, and the through hole is also drilled in the corresponding portion of the piston housing (9) so that the pump chamber of the injection pump and the communication unit (10) are in communication with each other. In the left half piston 1a, the through hole 6 is penetrated back and forth so that the low pressure chamber 5 and the space 8 communicate with each other through the through hole 6.

According to the present invention configured as described above, when the engine rotates, the fuel supply pump 42 in the injection pump is operated by the rotation of the drive shaft 41 in the injection pump, so that the fuel in the fuel tank 43 enters the injection pump and supplies fuel. As the pressure in the pump 42 increases and the rotation of the engine increases, the room pressure of the fuel supply pump 42 gradually increases, and the pressure increases the linkage 10 and the orifice 4 of the right upper piston 1b. The piston spring (2b) is pushed into the high pressure chamber (7) by pushing the right piston (1b). At this time, the piston spring (2b) is larger than the piston spring (2b). ) Is compressed but the timer spring 2a is hardly contracted by the initial set force and the reaction force of the roller holder assembly 11 which is connected to the left half piston la and the pin 3.

Then, as the rotation speed increases further, the piston spring 2b is further compressed, finally overcoming the initial set force of the timer spring 2a and the reaction force of the roller holder assembly 11, and gradually compressing at point a as shown in FIG. In this case, the displacement of the left half piston (1a) connected to the roller holder assembly (11) by the pin (3) is the force pushing the piston spring (2b) and the pushing force in the opposite direction to the timer spring (2a) It is offset so that the timer spring (2a) is moved little by little as the displacement is compressed to slowly rotate the roller holder assembly 11 is to advance the timer device (see Fig. 2 (b) (c)), As the engine speed is further increased, the pressure in the fuel supply pump is further increased, so that the right half piston 1b finally comes into contact with the left half piston 1a (see FIG. 2 (d)) and the piston spring 2b. Of The movement is lost and the displacement of the left half piston 1a is operated by the displacement of the timer spring 2a at the fourth b point, so that the true displacement of the injection timing is increased more sharply than before (see FIG. 2 (e)).

In this process, when the pressure of the space 8 increases, the pressure is released through the through hole 6 and the opening 5 ', and as shown in FIG. 2 (bar), the tip of the left half piston 1a When the roller housing 9 comes into contact with the piston housing 9, the rotation of the roller holder assembly 11 no longer occurs even if the engine speed increases (see FIG. 4C).

As described above, the present invention can increase the advance amount of the timer more rapidly by moving the left and right pistons by appropriately adjusting the parameters of the timer spring and the piston spring as the engine speed increases above a certain standard of medium and high speed. It is a very useful design that can improve the performance of the diesel engine with a simple timer device because it can accelerate the injection timing of the engine.

Claims (3)

In the timer device which controls the fuel injection timing by connecting the roller holder 34 with the pin 3, the support protrusion of the piston spring 2b is formed in the rear end, and the insertion space of the timer spring 2a is provided in the front end. The left half piston (la) having a portion and the right half piston (1b) having the support projection of the piston spring (2b) at the front end are provided in the piston housing (9) so as to be separated from each other, and the right half piston (1b) The orifice 4 is formed so that the pump fuel pressure can be transmitted to the high pressure chamber 7 side, and the left and right pistons 1a are interposed between the left and right pistons 1a and 1b via a piston spring 2b. Spacer (8) is formed between (1b), the low-pressure chamber (5) is formed in front of the left half piston (la) is a timer device for a diesel engine fuel injection pump, characterized in that the configuration. The low pressure chamber (5) and the space (8) is configured to communicate with each other through the through hole (6) by installing a through hole (6) through the left and right piston (1a). Timer device for fuel injection pump for diesel engine. The left and right pistons (1a) and (1b) according to claim 1, wherein the constants of the timer spring (2a) and the piston spring (2b) are appropriately adjusted as the engine speed of the diesel engine increases above a certain standard of medium and high speed. A timer device for a fuel injection pump for a diesel engine, characterized in that the fuel injection pump is configured to make the advancement of the fuel injection timing more rapid by moving the engine.