JP2579219B2 - Distribution type fuel injection pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention mainly relates to a distribution type fuel injection pump applicable to a four-cylinder two-cycle diesel engine.

[Conventional technology]

Conventionally, a distribution type fuel injection pump for a diesel engine rotates a plunger having one distribution hole in a cylinder fixed to a pump body, as described in, for example, Japanese Utility Model Laid-Open No. 54-137615. When the distribution hole communicates with the distribution passage provided in the cylinder, fuel is sent out to the distribution passage and can be injected into the combustion chamber of each cylinder. However, recently, there has been a tendency to adopt diesel engines in passenger cars, and high-speed diesel engines have been developed for this purpose. In this case, the number of revolutions of the fuel injection pump increases as the engine speed increases. . However, when a conventional distribution type fuel injection pump is used for high-speed rotation with the same structure as that of the conventional pump, wear of parts of the pump is severe, and in particular, there is a problem that wear of cam lobes of a cam disk for reciprocating a plunger becomes severe. . In order to solve this problem, Japanese Utility Model Application Laid-Open No. 59-65975 discloses that
In the conventional plunger type distribution type fuel injection pump,
By providing two distribution ports on the plunger and distributing passages of the same number as the number of cylinders in the cylinder in which the plunger is fitted, the number of rotations of the pump can be reduced, and high speed can be achieved without significantly changing the structure of the conventional fuel injection pump. We provide a distribution type fuel injection pump applicable to diesel engines. The above proposals disclose respective embodiments for the case of an engine having two cylinders, three cylinders, and four cylinders. FIG. 5 shows a cylinder 11, a pump plunger 6 fitted therein, a suction port 12 formed in the cylinder 11, a distribution passage 9 (each of the cylinders A and B of the engine) for the above-described four-cylinder engine. , C, D, corresponding to 9 _A , 9 _B , 9 _C ,
9 _D) and the distribution port 8 bored in the plunger (8 _a, 8 _b)
And the arrangement of suction groups 7 engraved at equal intervals at the tip of the pump plunger by a cross-sectional view. (See FIG. 1 for a longitudinal sectional view of the pump plunger 6.) As shown in the figure, a distribution passage 9 for sequentially feeding fuel to each cylinder under pressure.
Are provided equal to the number of cylinders (9 _A , 9 _B , 9 _C , 9 _D ), and the respective passages are arranged at equal intervals of 45 ° on the semicircle of the cylinder 11. When the pump plunger 6 rotates while reciprocating, for example, the suction group 7
Plunger 6 retracts when suction port 12
Then, when the plunger 6 rotates, the suction port 12 is closed, the plunger 6 moves forward, and the fuel in the cylinder 11 is distributed to the distribution port 8 while being compressed to a high pressure. and the passage 9 match, the injection of fuel is performed in the cylinder a in the engine corresponding to the distribution channel for example 9 _a at that time.

[Problems to be Solved by the Invention] In the above-mentioned conventional high-speed diesel engine, fuel injection is performed once for each cylinder for every two revolutions of the engine in four cycles. Since the fuel injection is performed once for each cylinder, the required rotation speed of the fuel injection pump is twice that of a four-cycle engine, and a high rotation speed of the injection pump is required as in the case of a high-speed diesel engine. You. Therefore, for the two-stroke diesel engine, as in the above case, two distribution holes 8 are provided in the plunger 6,
It is necessary to use a high-speed fuel injection pump.

In the case of a conventional four-cylinder diesel engine fuel injection pump, the distribution passage 9 is arranged on the semicircle of the cylinder 11 as shown in FIG. In this case, the high-pressure fuel filled in the two distribution ports 8 provided in the pump plunger 6 is sequentially distributed to the distribution passage 9 on the semicircle according to the rotation of the plunger 6. closed distribution port side, for example, the outlet of the dispensing port 8 _b in the case of a distribution port 8 _a and distribution passage 9 _a is through the Ri hydraulic pressure or to closed with a cylinder inner wall, in that the reaction force the plunger 6 is a uneven contact to the dispensing passage 9 _a side. Therefore, when the distribution passage 9 is unevenly distributed on the semicircle, uneven wear occurs on the side of the cylinder 11 where the distribution passage is provided. Further, since the distribution passage 9 is unevenly distributed on the semicircle, the distribution passage 9 up to the delivery valve 13 (see FIG. 1) is provided.
Processing and the arrangement of the delivery valve 9 have a small degree of freedom, resulting in design restrictions and a disadvantage in strength.

In view of the above problems, in the present invention, uneven wear occurs in a cylinder of a pump plunger in a fuel injection pump used mainly in a two-cycle diesel engine and also in a high-speed four-cycle diesel engine. It is an object of the present invention to provide a distribution-type fuel injection pump which has no strength, has sufficient strength, and is easy to design and manufacture.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, there is provided a pump plunger rotating and reciprocating, and a cylinder accommodating the plunger, and a distribution port formed in the plunger and a cylinder formed in the cylinder. A distribution type fuel injection pump for pumping fuel to the injection nozzle of each cylinder through the distribution passage by communication with the distribution passage.
A pair of distribution ports, which penetrate the axis of the plunger and are opened on the peripheral side surface of the plunger, are provided in the plunger;
4 communicates with the distribution port according to the rotation of the plunger
A plurality of distribution passages are provided in the cylinder, and the distribution passages are arranged at intervals of 45 °, 90 °, 135 °, and 90 ° in the circumferential direction of the cylinder. Provided is a distribution type fuel injection pump for a cylinder diesel engine.

A pump plunger that rotates and reciprocates; and a cylinder that houses the plunger. Each of the pump plungers communicates with a distribution port formed in the plunger and a distribution passage formed in the cylinder through a distribution passage. In a distribution type fuel injection pump for pumping fuel to an injection nozzle of a cylinder, two pairs of distribution ports penetrating the axis of the plunger and opening on the peripheral side surface of the plunger are provided in the two sets of plungers. The two sets are disposed in the plunger so as to be arranged at a fixed distance from each other in the axial direction of the plunger and to be inclined at an angle of 45 ° in the circumferential direction of the plunger. A structure in which four distribution passages communicating with the distribution port in accordance with the rotation of the cylinder are provided in the cylinder, and the distribution passages are arranged at equal intervals in a circumferential direction of the cylinder. Providing 4-cylinder distributor type fuel injection pump for diesel engines, characterized in that.

(Operation)

The distribution ports alternately communicate with the four distribution passages arranged at intervals in the circumferential direction of the inner wall of the cylinder as the plunger rotates, and each time high-pressure fuel enters the distribution passage from the distribution port, The fuel is fed to the injection nozzles of the cylinders and fuel injection is performed in each cylinder. At this time, since the distribution passage is arranged so as not to be unevenly distributed in a specific direction in the circumferential direction, the plunger does not hit against the cylinder wall.

〔Example〕

FIG. 1 is a schematic sectional view of a distribution type fuel injection pump 20 according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes a drive shaft, which is a crankshaft of a diesel engine (not shown).
In the case of a 4-cycle engine in conjunction with
The engine is designed to rotate at four rotation speeds and, in the case of a two-cycle engine, at half the engine speed. A cam disk 5 coaxial with the drive shaft 1 is reciprocally connected to the drive shaft 1, and a cylindrical pump plunger 6 coaxial with the cam disk 5 is integrally formed on the right end surface of the cam disk 5. Eight cam ridges 4 are formed at equal intervals around the axis of the cam disk 5 on the left peripheral end face in the figure. A disk-shaped roller 3 having an axis perpendicular to the axis of the cam disk 5 is mounted on the roller ring 2 at the lower left of the cam disk 5 shown in FIG. The right side surface of the roller 3 is in contact with the peripheral end of the left side surface of the cam disk 5 in FIG.

Further, the pump plungers 6 are drilled lateral hole 6 _b is from the distal end surface inwardly at its central portion, FIG. 1 the left end of the lateral hole 6 _b are the same and orthogonal to the axis of the plunger 6 It is open to a vertical hole (spin port) _6c provided therethrough. A control sleeve 14 provided for adjusting the fuel injection amount is fitted on the plunger 6, and the vertical hole _6c is opened and closed by the controller sleeve 14. Further, the distribution ports 8 extending through the plunger 6 is perpendicular to the axis of the transverse hole 6 _b to claim surface 6 _a and the longitudinal hole 6 _c Tonoho Isuzu center of the plunger 6 is bored, Figure 2 (II in Fig. 1
As shown in -II sectional view), the distribution port 8 consists of a set of two dispensing ports 8 _a, 8 _b, for example the horizontal hole of said distribution port 6
When the first diagram portion of _b and first dispensing ports 8 _a, the lower portion and the second dispensing ports 8 _b becomes, than the diameter of the dispensing port 8 _a, 8 _b open end of the distribution port It is formed a little wider. The peripheral wall of the top end of the plunger 6, as illustrated inhalation Group _{7 (7 a, 7 b,} 7 c, 7 d, 7 e, 7 f, 7 g, 7 h) is the distribution port 8 _a, 8 _b Are arranged at 45 ° angle intervals in such a manner that they are distributed from the axis of
7 _{a to} 7 _h extend in the axial direction of the plunger 6 and are formed in a substantially rectangular parallelepiped shape.

A spring receiving plate 15 is fitted to the right side of the cam disk 5 of the plunger 6, and a spring receiving plate 15 is provided between the spring receiving plate 15 and the pump body 21.
The cam disk 5 and the plunger 6 are always urged leftward in FIG. When the cam disc 5 rotates, the plunger 6 moves to the right in FIG. 1 while rotating whenever the cam peak 4 rides on the roller 3, and the fuel in the high pressure chamber 22 is distributed to the distribution port 8 and the distribution port communicating therewith. It is sent out to the delivery valve 13 for each cylinder 4 through the passage 9.

With reference to Figure 2, when the description of the distribution action of the fuel, of dispensing ports 8 _a the distribution passage 9 at this time in a state in which the fuel is fed through the cylinder A to _A cam disk 5 of FIG cam mountain 4-1 (referred to as a cam top eight 4-1 to 4-8) is pushed the plunger 6 moves in Figure 1 the right to the roller 3, the fuel in the high pressure chamber 22 pumped from the dispensing port 8 _a Is done. Then, the plunger 6 communicates with the dispensing port 8 _b and distribution passage 9 _c is When this work the following cam lobes 4-2 rotates 45 degrees in the direction of the second arrow shown with the cam disc 5, the cylinder C Fuel is pumped. Further, when the plunger 6 is rotated following the dispensing ports 8 _a communicates with the distribution passage 9 _B, the cam 4-3 work, the leads to the distribution port 8 _b are distribution channel 9 _D the next, acts cam 4-4, With this, four cylinders A ~ with 1/2 rotation of the plunger 6
One fuel injection is performed in D, and thereafter, two fuel injections are performed in each cylinder in one rotation of the plunger 6 in the same manner. During the rotation of the plunger 6, for example, the cam peak 4-1
A plunger 6 is retracted to the left in FIG. 1 by the urging force of the spring 16, the suction group 7 communicates with the suction port 12, and the high pressure chamber 22 is filled with fuel. It is. For example suction Group 7 _a plunger 6 from the state of FIG. 2 rotates 22.5 ° in the direction of the arrow matches the position of the suction port 12, the fuel enters the high pressure chamber 22 both communicate with each other. At this time, the distribution ports _8a and _8b are both closed by the wall surface of the cylinder 11. Furthermore the plunger 6 is communicated with the the distribution port 8 _b is distribution passage 9 _c to 22.5 °, injection is performed. Further communicates suction Group 7 _b and the suction port 12 to 22.5 °, supply to the chamber 22 of the fuel is performed, the same operation is repeated. Spacing as distribution passage 9 _A to 9 _D shown is 45 degrees without the position 4 equal portions circumferentially, 90 °, 135 °, but are 90 ° reason is that in this case, if distribution channel 9 When the circumference is 90 ° arranged in four equal parts i.e. equidistant to this distribution port a set of two types will be leading to two distribution passages distribution port 8 _a and 8 _b are simultaneously in two cylinders This is to avoid inconvenience of simultaneous fuel injection and explosion. By setting the above gap, fuel injection is always performed at equal intervals to the four cylinders, and the engine can be smoothly rotated.

3 and 4 show a second embodiment of the present invention. 3 shows a part of the plunger 6, FIG. 3 (a) is a longitudinal sectional view, FIG. 3 (b) is a sectional view taken along the line BB of FIG. 3 (a), and FIG. FIG. 3 shows a partially enlarged cross-sectional view of the plunger 6 and the cylinder 11 in a BB portion. The difference from the first embodiment is that the distribution port 8 of the plunger 6 and the cylinder 11
Since the other parts of the arrangement of the distribution passage 9 are the same as those of the first embodiment, the description thereof will be omitted.

The plunger 6, and a set of two dispensing ports 8 _a, 8 _b,
Forms an angle of 45 ° in the circumferential direction of the dispensing port 8 _a, 8 _b and the plunger, dispensing ports 8 _a, 8 _b and shifting one other spaced at regular intervals in pairs of two distribution in the axial direction Ports 8 _c and 8 _d are formed so as to penetrate perpendicularly to the axis of the plunger 6, whereas the distribution port 8 _a , 8 _b ,
Four distribution passages 9 _A , 9 _B , 9 _C , 9 _D corresponding to 8 _c , 8 _d are arranged at 90 ° intervals in the circumferential direction (FIG. 4).

With the above configuration, a set of two dispensing ports 8 _a, 8 _b are distribution passage 9 _A → 9 every 90 degrees during one rotation of the plunger 6 _B →
Communicate in the order of 9 _A → 9 _B , and another pair of two distribution ports 8 _c , 8 _d
Is 9 _C → 9 _D → 9 _C → 9 _D every 90 ° during one rotation of plunger 6
Communicate with Therefore, while the plunger 6 makes one rotation, the distribution port 8 communicates with the distribution passage 9 at intervals of 45 ° with 9 _A → 9 _C → 9 _B → 9 _D → 9 _A → 9 _C → 9 _B → 9 _D. I do. Fuel supply with respect to the high-pressure chamber 22 of the via inhalation Group 7 than in the suction port 12 (7 _a ~7 _h) during this time will not be described because it is similar to the first embodiment. Thus, also in the present embodiment, the fuel injection is always performed at equal intervals for each cylinder.

According to the above-described embodiment, since the distribution passage is not unevenly distributed on the semicircle as in the conventional example, the plunger is not biased to the cylinder and uneven wear does not occur.

Also, since the distribution path start end is not unevenly distributed, the delivery valve
Processing of the distribution passages up to 13 and arrangement of the delivery valve 13 are easy and advantageous in strength.

Also, when this type of distribution type fuel injection pump is mounted on a two-stroke engine and the rotation speed of the injection pump is set to 1/2 of the engine rotation speed, the ratio of the rotation speed of the injection pump to the engine becomes In the conventional four-stroke engine, the ratio of the number of revolutions of the pump to the engine when the fuel injection pump having one distribution port is mounted in the conventional pump plunger is the same. Therefore, the drive components such as the timing pulley can be shared with the conventional fuel injection pump for a four-stroke engine. Also, there is no need to change the feed pump or the like to the fuel injection pump, and there is no danger that its durability or the like will be reduced.

The present invention can be applied not only to a four-cylinder two-cycle diesel engine but also to a four-cylinder four-cycle diesel engine or a diesel rotary engine. In particular, the durability of the pump is increased by increasing the rotation speed of the fuel pump. Therefore, it is suitable for use in future high-speed engines.

〔The invention's effect〕

 The following effects are achieved by implementing the present invention.

(1) By disposing the distribution passages at intervals in the circumferential direction, one-side contact of the plunger due to the hydraulic reaction force is eliminated, and uneven wear of the cylinder is prevented.

(2) Since the distribution path start end is not unevenly distributed, the processing of the distribution path to the delivery valve and the arrangement of the delivery valve are easy, and the strength is advantageous.

(3) The rotation speed of the fuel injection pump can be made lower than the engine rotation speed, and the durability of the pump is improved.

[Brief description of the drawings]

1 is a schematic sectional view of a distribution type fuel injection pump according to a first embodiment, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 (a) is a pump plunger of the fuel injection pump of the second embodiment. FIG. 3 (b) is a cross-sectional view taken along line BB of FIG. 3 (a), FIG. 4 is a partially enlarged cross-sectional view of the pump plunger and the cylinder at the line BB, FIG. 5 is a partially enlarged cross-sectional view of a distribution port portion between a pump plunger and a cylinder of a conventional four-cylinder engine. 6: Pump plunger, 8: Distribution port, 9: Distribution passage, 11: Cylinder, 20: Distribution type fuel injection pump.

Continued on the front page (72) Inventor Tadashi Fukuyama 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Shinji Kamoshita 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Invention Toyoichi Umeka 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Koichi Nakae 1 Toyota Town Toyota City, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Kushi Nakajima Aichi Prefecture 1-1, Showa-cho, Kariya-shi Japan Denso Co., Ltd. (56) References JP-A-57-188761 (JP, A)

Claims (2)

(57) [Claims] A pump plunger which rotates and reciprocates; and a cylinder accommodating the plunger. The distribution passage is formed by communication between a distribution port formed in the plunger and a distribution passage formed in the cylinder. In a distribution type fuel injection pump for pumping fuel to an injection nozzle of each cylinder via a plunger, a set of two distribution ports penetrating through an axis of the plunger and opening on a peripheral side surface of the plunger is provided in the plunger. Four distribution passages communicating with the distribution port according to the rotation are provided in the cylinder, and the distribution passages are arranged at intervals of 45 °, 90 °, 135 °, and 90 ° in the circumferential direction of the cylinder. A distribution type fuel injection pump for a four-cylinder diesel engine, characterized in that: 2. A pump according to claim 1, further comprising: a pump plunger rotating and reciprocating; and a cylinder accommodating the plunger. The distribution passage is formed by communication between a distribution port formed in the plunger and a distribution passage formed in the cylinder. A distribution type fuel injection pump for pumping fuel to an injection nozzle of each cylinder via a plunger axis, and two pairs of distribution ports opened on the peripheral side surface of the plunger are provided in the two pairs of plungers; The two sets of the distribution ports are arranged in the plunger so as to be kept at a fixed distance from each other in the axial direction of the plunger and to be inclined at an angle of 45 ° in the circumferential direction of the plunger. Then, four distribution passages communicating with the distribution port according to the rotation of the plunger are provided in the cylinder, and the distribution passages are arranged at equal intervals in a circumferential direction of the cylinder. A four-cylinder diesel engine distributor type fuel injection pump, characterized in that the.