JPH0442504Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a fuel injection device that increases the amount of fuel only to specific cylinders that are likely to cause half-misfires (including misfires).

(Prior Art) Some diesel engines tend to cause partial misfires in certain cylinders during warm-up. Normally, the cylinders that are likely to cause this half-misfire are limited to certain cylinders in the same engine model due to the arrangement of cooling channels, etc., but in order to prevent this half-misfire, Previously, Utsukai Showa 56-99058
As shown in the publication, the solution was to increase the amount of fuel to all cylinders during warm-up.

However, increasing the amount of fuel for all cylinders in this manner is undesirable in terms of fuel efficiency and exhaust gas countermeasures.

(Purpose of the invention) This invention was made taking into account the above-mentioned circumstances, and is designed to prevent half-misfires in specific cylinders by increasing the amount of fuel only for specific cylinders that are prone to half-misfires. The purpose of the present invention is to provide a fuel injection device that achieves the following.

(Structure of the invention) In order to achieve the above-mentioned object, in the present invention, the fuel injection device injects fuel introduced into the intake slit of the plunger through the main suction passage by the reciprocating rotational movement of the plunger. Utilizing the fact that the engine is pressurized, an intake passage for increasing the amount of fuel is provided to introduce fuel into the intake slit. By controlling the plunger periodically with the rotation of the plunger by the control device, the fuel from the increase intake passage is fed under pressure only to a specific cylinder.

(Example) Hereinafter, an example in which the present invention is applied to a four-cylinder diesel engine will be described based on the attached drawings.

In FIG. 1, A indicates a so-called VE type distribution type fuel injection pump. To explain this, a plunger 3 is rotatably and slidably inserted into a barrel 2 integrated into a casing 1. has been done. Further, a drive shaft 4 is rotatably held in the casing 1 in series with the plunger 3, and the drive shaft 4 supports a vane type pump 5 in addition to the plunger 3.
A governor mechanism 6, which will be described later, is rotatably driven. Of course, the drive shaft 4 is
It is rotationally driven by the output shaft 7a of the engine 7 shown in FIG.

A fuel storage chamber B filled with fuel discharged from the pump 5 is formed in the casing 1, and this fuel storage chamber B is opened into the barrel 2 via the main suction passage 8. Inside this barrel 2, a pressure chamber D is defined by a plunger 3, and on the outer periphery of the tip of the plunger 3, four intake slits 9 corresponding to the number of cylinders are provided at intervals in the circumferential direction. The fuel is supplied to the pressure chamber D when the intake slit 9 is aligned with the main intake passage 8 according to the rotational and sliding position of the plunger 3. Further, a discharge passage 10 that is always open to the pressure chamber D is formed in the plunger 3, and one discharge port 11 that is continuous with the discharge passage 10 and opens on the side surface of the plunger 3 is formed. Four distribution ports 12 corresponding to the number of cylinders are opened on the circumferential surface of the barrel 2 at intervals in the circumferential direction, and the plunger 3
The discharge port 11 is sequentially communicated with the distribution port 12 depending on the rotation and sliding position of the dispensing port 12 . Of course, each distribution port 12 is connected to each cylinder via piping 13A to 13D shown in FIGS. 2 and 3.
Fuel injection nozzles 14A-14D for _C1 - _C4
connected to either.

With the above-described configuration, the plunger 3
is the pressure chamber D depending on its rotation and sliding.
(expansion of pressure chamber D and communication of intake slit 9 with main intake passage 8);
The fuel in the pressure chamber D is compressed (compression of the pressure chamber D and communication between the discharge port 11 and the distribution port 12) is carried out, and the fuel is pumped to the fuel injection nozzles 14A to 14D in a predetermined order. In order to set a predetermined sliding position according to the rotational position of the plunger 3,
A cam plate 15 is integrated with the plunger 3,
4 according to the number of cylinders protruding from the cam plate 15
By sequentially contacting the roller 16, the two cam surfaces 15a can take a predetermined sliding position depending on the rotational position of the cam surface 15a. Note that this roller 16 is slightly displaced in the circumferential direction of the cam plate 15 via a rod 19 by a spool valve 18 of an advance angle device 17 that is displaced in accordance with the fuel pressure from the pump 5. As a result,
The fuel injection timing is advanced according to the engine speed.

To adjust the amount of fuel to the fuel injection nozzles 14A to 14D, the control sleeve 20, which is slidably fitted on the outer periphery of the plunger 3, is inserted into the lever mechanism 21,
Control lever 2 via spring 22
This is done by operating 3. That is,
The plunger 3 is formed with a relief port 24 that is connected to the discharge passage 10 and opens into the fuel storage chamber B. The opening timing of the relief port 24 (the effective stroke of the plunger 3) is determined by the control sleeve 20 relative to the plunger 3. It is adjusted by relative displacement. Further, the position of this control sleeve 20 is determined by the governor mechanism 6 mentioned above.
For this reason, a flyweight 26 is provided to rotate integrally with the gear 25B that meshes with the gear 25A integrated with the drive shaft 4, so that the engine rotation speed, that is, the drive shaft The amount of displacement of the flyweight 26 corresponding to the number of rotations of the gear 25B is transmitted to the lever mechanism 21 via a sleeve 28 that is slidable on a shaft 27 that holds the gear 25B. Note that the lever mechanism 21 is held by a throttle plate 29 that adjusts the amount of fuel supplied to the main intake passage 8. In addition, the main suction passage 8
is opened and closed by an electromagnetic cut-off valve 30.

Since the configurations of the parts described above are known, further detailed explanation will be omitted, and next, the configurations that are the characteristic parts of the present invention will be explained.

A suction passage 31 for increasing the quantity is opened into the barrel 2 and is connected to the fuel storage chamber B, and an electromagnetic on-off valve 32 is connected to the middle of the suction passage 31 for increasing the quantity. The intake passage 31 for increasing the amount is for a cylinder that is likely to cause half-misfire, for example, the fourth cylinder _C4 . Therefore, the fuel from the intake passage 31 for increase is introduced into the pressure chamber D via the intake slit 9, but the fuel from the intake passage 31 for increase is introduced into the distribution port 12 for the fourth cylinder _C4 . The on-off valve 32 is opened in synchronization with the rotation of the plunger 3 so that the oil is fed only under pressure. The opening position of the intake passage 31 for increasing the amount is set at a position 180 degrees opposite to the main intake passage 8 in the circumferential direction of the plunger 3, so that one intake slit 9 is connected to the main intake passage 8 and the intake passage for increasing the amount. 31 at the same time.

An example of a control system that controls the on-off valve 32 is shown in the third example.
To explain with a diagram, 33 in the figure is a control unit as a control device, and this control unit 33 receives exhaust temperature signals from exhaust temperature sensors 35 and 36 in addition to the rotation speed signal _S1 of the engine rotation speed sensor 34. S ₂ , S ₃ and engine output shaft 7
A, that is, a rotation angle signal _S4 from an angle sensor 37 that detects the rotation angle position of the plunger 3 is input. The above exhaust temperature sensor 35
The exhaust temperature sensor 36 detects the temperature of the fourth branch exhaust pipe 38D of the exhaust mainifold 38 connected to the fourth cylinder _C4 , which is likely to cause half-misfire, and the exhaust temperature sensor 36 detects the temperature of the fourth branch exhaust pipe 38D of the exhaust mainifold 38, which is connected to the fourth cylinder C4, which is likely to cause half-misfire. 3 cylinders
The temperature of the third branch exhaust pipe 38C connected to _C3 is detected.

The control unit 33 compares the outputs of both exhaust temperature sensors 35 and 36, and when the temperature of the fourth branch exhaust pipe 38D is lower than the temperature of the third branch exhaust pipe 38C, a half-misfire occurs in the fourth cylinder _C4 . It has a function to distinguish what is occurring. Then, when the plunger ₃ reaches a predetermined rotation angle based on the rotation angle signal _S4 while this half-misfire is occurring, assuming that it is rotating at idle based on the rotation speed signal S1. That is, when the intake slit 9 for the fourth cylinder _C4 as a specific cylinder is communicated with the main intake passage 8, the on-off valve 32 is opened. This causes the 4th cylinder, which is causing half-misfire, to
As a result, in addition to the fuel from the main intake passage ₈ , fuel is supplied to C 4 from the intake passage 31 for increase through the intake slit 9 for cylinders other than the fourth cylinder C ₄ . Half-misfire of the 4-cylinder _C4 is prevented.

Here, the amount of fuel to each cylinder is theoretically determined by the fuel pressure supplied to the pressure chamber D and the relief port 2.
It is determined by the closing timing of 4. On the other hand, in reality, since the plunger 3 reciprocates even at low engine speeds, the volume from the pressure chamber D to the relief port 24 via the discharge passage 10 is not filled with fuel. In other words, it is difficult for fuel to enter the discharge passage 10. Furthermore, if fuel is supplied through more intake slits than through one intake slit, the cross-sectional area of the passage for fuel supply becomes larger, and fuel is more fully supplied to the discharge passage 10. Therefore, this more sufficient fuel supply ultimately results in an increase in the amount of fuel to a specific cylinder.

Note that when the engine speed reaches a predetermined number of revolutions or higher, the operating range is such that half-misfire no longer occurs, so the on-off valve 32 remains closed. Further, the engine is stopped by closing both the cut-off valve 30 and the on-off valve 32.

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

For example, when the cooling water temperature is below a predetermined temperature, it is assumed that a half-misfire has occurred, and on the premise that the engine is warming up, the air is injected to increase the amount of air in the cylinder where half-misfire is likely to occur, regardless of other operating conditions. The amount of fuel may be increased through the passage 31.

If there are multiple cylinders that are likely to cause half-misfires, the opening timing of the on-off valve 32 may be set so that fuel can be pumped to these multiple cylinders, or the opening and closing timing of the on-off valve 32 may be set so that the fuel can be pumped to these multiple cylinders, or the intake passage for increasing the amount of air can be opened and closed for each of these multiple cylinders. The valves may be provided separately.

Normally, cylinders that are prone to half-misfires are identified for each engine model, but if the cylinders that are prone to half-misfires cannot be identified, for example, exhaust temperature sensors may be installed on the branch exhaust pipes of all cylinders. By doing so, the cylinder in which the half-misfire is occurring can be identified.

Whether or not a half-misfire has occurred can be determined by any appropriate means, such as by checking the exhaust gas temperature, by checking the cylinder temperature, or by checking the engine vibration.

(Effects of the invention) As is clear from the above, the invention has the following effects:
Since we increased the amount of fuel only to a specific cylinder to prevent half-misfires in that specific cylinder, the fuel consumption is lower than when increasing the amount of fuel to all cylinders to prevent half-misfires. It is possible to obtain something favorable in terms of improvement and exhaust gas countermeasures.

In addition, in this invention, the fuel for increase is supplied to a specific cylinder using the existing intake slit, so it is easy to control the increase in fuel to a specific cylinder, and this increase in fuel can be done with high precision. can be done.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an example of a fuel injection pump to which the present invention is applied. FIG. 2 is a perspective view showing a fuel supply system and a fuel pressure delivery system to the plunger portion. FIG. 3 is a system diagram showing an example of a control system according to the present invention. 3...Plunger, 8...Main suction passage, 9...
Intake slit, 10...Discharge passage, 12...
...Distribution port, 13A-13D...Piping, 14A-1
4D...Fuel injection nozzle, 31...Increase intake passage, 32...Opening/closing valve, 33...Control unit (control device), A...Fuel injection pump, _C1 ~
C ₄ ……Cylinder.

Claims (1)

[Claims for Utility Model Registration] A number of intake slits corresponding to the number of cylinders are formed at intervals in the circumferential direction of the plunger on the outer periphery of the tip of the plunger that rotates in a reciprocating manner, and intake slits are formed at intervals in the circumferential direction of the plunger, and In a fuel injection device for a multi-cylinder diesel engine, the fuel injection device for a multi-cylinder diesel engine is configured to force-feed fuel introduced into the plurality of intake slits to the engine via a main intake passage through which the plurality of intake slits are sequentially communicated. a suction passage for increase in volume, which is positioned so as to communicate with the plurality of intake slits in sequence, and to communicate with other intake slits other than the intake slit with which the main suction passage communicates; an opening/closing valve that opens and closes the intake passage for the intake passage; and when an intake slit for a specific cylinder among the plurality of intake slits is communicated with the main intake passage, the intake passage for increasing the intake is opened and closed through another intake slit. A fuel injection device comprising: a control device that opens the on-off valve in synchronization with rotation of the plunger so that fuel is pumped through the passage.