JPH04194359A - Distributor type fuel injection pump - Google Patents

Abstract

PURPOSE:To eliminate any combustion failure attributable to pressure defective in a combustion chamber by forming each intake groove, installed on an outer circumferential surface of a plunger in the circumferential direction, in a spiral or rectilinear form in parallel with the relatively moving locus of an intake port with the plunger at time of a pressure-feed stroke. CONSTITUTION:If such a case as applied to a 6-cylinder engine is exemplified, right inclination is an intake stroke and left inclination a pressure-feed stroke, respectively, in the relative moving locus (shown in a broken line) of an intake port 4 with a plunger 1, and the range of a slanting line is a full-line moving locus range of the intake port 4 at time of this pressure-feed stroke. A turning angle alpha for a portion of one cylinder of the plunger 1 is set down to a pressure-feed stroke of this plunger 1. A range, not overlapped with the moving locus at time of the pressure-feed stroke of the intake port 4 is the setting allowable width of an intake groove 6, utilizing it effectively, and this intake groove 6 of groove width L is formed. In addition, the intake groove 6 being formed like this has a tilt to the axial direction of the plunger 6, so that the form comes to a spiral form. At an intake process, the intake port 4 is interconnected to the intake groove 6 on a wide passing section, through which a fuel intake quantity is thus increasable.

Description

[Detailed description of the invention]

[00011

[Industrial Application Field] The present invention relates to a fuel distribution pumping mechanism of a distribution type fuel injection pump used in a day cell engine, and particularly to a fuel distribution pumping mechanism. [0002] [0002] FIG. 4 shows a fuel distribution and pressure feeding mechanism in a conventional general distribution type fuel injection pump. The plunger l in this fuel distribution and pumping mechanism section draws in and pumps fuel by performing reciprocating linear motion and rotational motion within the plunger barrel 2. That is, the plunger l has the same number of suction grooves 6 as the number of cylinders of the engine, which communicate with the suction port 4 of the fuel supply passage 3 formed in the plunger barrel 2 during the suction stroke and suck fuel into the pressure chamber 5. , a vertical hole 8 and a distribution groove 9 for communicating with one of the distribution passages 7 formed in the plunger barrel 2 corresponding to each cylinder during the pumping stroke to forcefully feed the fuel in the pumping chamber 5 to the injection nozzle of the cylinder. The suction grooves 6 provided at equal intervals on the outer peripheral surface of the plunger j (7) are formed in a straight line parallel to the axial direction of the plunger 1. [0003] Further, the plunger l has a face cam 10 having the same number of cam ridges as the number of cylinders, and this face cam 10 is pressed against a roller 11 by a spring (not shown). Then, the plunger l performs reciprocating motion several times in the cylinders along the profile of the face cam IO during one rotation by the drive shaft (not shown), thereby sequentially distributing the fuel sucked into the pressure feeding chamber 5 to each cylinder. It is pumped. FIG. 5 is an explanatory diagram of the action of the suction stroke, and FIG. 6 is an explanatory diagram of the action of the pumping stroke. Note that the pressure feeding of the fuel ends when the spill port [2 of the plunger l comes off the spill ring 13 and opens into the pump chamber. As a distribution type fuel injection pump for such a day cell engine, for example,
-1472 can be mentioned. [0004]

[Problem to be solved by the invention]

By the way, as described above, the plunger l rotates by a rotation angle corresponding to the number of cylinders in one reciprocation. Therefore, the outer circumferential width between the suction grooves 6 provided on the outer circumferential surface of the plunger 1 is such that even if the plunger 1 rotates during the pumping stroke, the suction s6
It is necessary to set the width (hereinafter referred to as suction groove setting allowable width) so that the suction groove and suction port 4 do not overlap. This intake groove setting allowable width becomes narrower as the number of cylinders increases. For example, in the case of a 6-cylinder engine, the set pitch of the suction groove is smaller by the number of cylinders than in a 4-cylinder engine, and in that case, the required pumping period in the engine is constant regardless of the number of cylinders, so the relative Therefore, the width of the suction groove 6 is narrow. [0005] As described above, since the conventional suction groove 6 is formed linearly in the axial direction of the plunger l, the permissible width of the suction groove is limited. If it is not used effectively and is applied to an engine with six or more cylinders, the inflow amount will be restricted due to the narrow communication area when communicating with the intake boat 4. Therefore, There is a problem in that the fuel suction efficiency decreases and the pressure in the combustion chamber is insufficient, making it impossible to obtain good combustion. This is an attempt to eliminate the above-mentioned problems by providing a suction groove that is effectively utilized.[0007]

[Means to solve the problem]

In order to solve the above problems, the present invention has the same number of intake grooves as the number of cylinders of the engine for communicating with the fuel intake port and sucking fuel into the pressure-feeding chamber during the intake stroke, and a groove corresponding to each cylinder during the pressure-feeding stroke. By causing a plunger provided with one distribution groove communicating with one of the distribution passages to force-feed the fuel in the pressure-feeding chamber to the cylinder concerned, to perform reciprocating motion and rotational motion for suction and pressure-feeding. In a distribution type fuel injection pump that distributes and pressure-feeds fuel to each cylinder, each of the suction grooves provided on the outer circumferential surface of the plunger at equal intervals in the circumferential direction is aligned with the locus of relative movement of the suction port with respect to the plunger during the pumping stroke. It is formed into a parallel spiral or an oblique straight line. [0008]

[Effect]

In the distribution type fuel injection pump according to the present invention, by forming the suction groove in a spiral or diagonal linear shape as described above, the suction groove is effectively formed between the relative movement locus of the suction port with respect to the plunger during the pumping stroke. can be formed into Therefore, the spiral or diagonally linear suction groove can have a wider groove width than the conventional linear suction groove parallel to the axial direction. As a result, the communication cross-sectional area between the suction port and the suction groove during the suction stroke can be set large, and the fuel suction efficiency can be increased. [0009]

[Example] Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 to 3. It should be noted that since the present invention relates to a fuel distribution pumping mechanism unit device in a distribution type fuel injection pump, in particular to the suction groove, illustrations and descriptions of the entire conventionally known distribution type fuel injection pump will be omitted, and the fuel distribution As for the pumping mechanism, the other structure except for the suction groove is the same as the conventional one, so the description thereof will be replaced by using the conventional view of FIG. 4. [00101] This embodiment is shown in the case where it is applied to a six-cylinder engine, and FIG. 1 is a perspective view of a plunger in a fuel distribution and pumping mechanism section, and FIG. 2 is a front view of the plunger. As shown in the figure, six suction grooves 6 are spirally formed at equal intervals in the circumferential direction on the outer circumferential surface of the plunger l, and these suction grooves 6 are used to provide suction to the plunger 1 during the pumping stroke. The shape follows the relative movement locus of the port 4. [00111] That is, FIG. 3 is a developed view of the plunger in the lateral (circumferential) direction, and in the same figure, the dashed line indicates the relative movement locus of the suction port 4 with respect to the plunger l, and the right slope is the suction stroke, and the left slope is the suction stroke. The slope is the pressure stroke, and the range shown by diagonal lines is the actual movement locus width of the suction port 4 during the pressure stroke. Further, in the figure, α indicates the rotation angle of the plunger 1 for one cylinder, and S indicates the pumping stroke of the plunger 1. [0012] Therefore, in FIG. 3, the range that does not overlap with the movement locus of the suction port 4 during the pressure feeding stroke is the allowable setting width of the suction groove 6, and this embodiment effectively utilizes this settable width of the suction groove. A suction groove 6 having a groove width is formed. In other words, the suction groove 6 is formed parallel to the locus of movement of the suction port 4 during the pumping stroke, and since the suction groove 6 formed in this way has an inclination with respect to the axial direction of the plunger 1, its shape becomes a spiral. Incidentally, the groove width L1 is shown in the case where a conventional linear suction groove parallel to the axial direction is formed in the suction groove setting allowable width. [0013] When the spiral suction groove 6 is formed in the plunger l in this way, as is clear from FIG. 2, it is possible to set the groove width to be larger than the conventional groove width L1. It is. Therefore, during the suction stroke, it is possible to communicate the suction port 4 with the suction groove 6 through a much wider passage cross section than in the past. As a result, in the distributed fuel injection pump according to this embodiment, the amount of fuel sucked from the suction port 4 with respect to the suction groove 6 can be increased, and the suction efficiency can be improved. [0014]Although the present embodiment has been described with reference to the case where the suction groove 6 is formed in a spiral shape, the effect can be obtained even if the suction groove 6 is formed in an oblique linear shape. However, in that case, the depth of the suction groove 6 will change somewhat, but it is fully effective as long as the inclination angle of the suction groove 6 does not become extremely thick. [0015]

【Effect of the invention】

As described in detail above, the distribution type fuel injection pump according to the present invention has a spiral suction groove that is parallel to the locus of relative movement of the suction port with respect to the plunger during the pressure stroke. Since it can be set to be thicker (as compared to Although the present invention is effective in diesel engines having six or more cylinders, there is no problem in applying it to a four-cylinder diesel engine.

[Brief explanation of the drawing] 【figure! ]

FIG. 2 is a perspective view showing a plunger provided with a suction groove of a distribution type fuel injection pump according to an embodiment of the present invention.

[Figure 2] Similarly, it is a front view of the plunger.

[Figure 3] FIG. 2 is an explanatory view of the plunger expanded in the lateral (circumferential) direction.

FIG. 4 is a sectional view of a fuel distribution and pressure feeding mechanism of a conventional general distribution type fuel injection pump.

[Figure 5] FIG. 6 is an explanatory diagram of the action of the plunger in the suction stroke.

[Figure 6] FIG. 3 is an explanatory diagram of the operation of the pumping stroke of the plunger.

[Explanation of symbols]

l Plunger 2 Plunger barrel 4 Suction port 6 Suction groove

[tlJ class name] Drawing Figure 1]

[Figure 2]

[Figure 3]

Claims (1)

[Claims] Claim 1: Suction grooves having the same number as the number of cylinders of the engine and communicating with the fuel intake port to suck fuel into the pressure chamber during the intake stroke, and communicating with one of the distribution passages corresponding to each cylinder during the pressure stroke. and one distribution groove for forcefully feeding the fuel in the pressure-feeding chamber to the cylinder concerned, the plunger is made to perform reciprocating motion and rotational movement for suction and pressure-feeding, thereby distributing fuel to each of the cylinders. In a distribution type fuel injection pump that performs pressure feeding, each of the suction grooves provided at equal intervals in the circumferential direction on the outer peripheral surface of the plunger is arranged in a spiral or diagonal shape parallel to the locus of relative movement of the suction port with respect to the plunger during the pumping stroke. Distribution type fuel injection pump formed in a straight line.