JPS5963362A - Fuel injection pump - Google Patents

Abstract

PURPOSE:In a jerk type fuel injection pump, to vary the valve opening pressure of a variable unloading delivery valve in accordance to the operating condition such as load, rotation, etc. by exciting a fixed iron core and attracting a movable core forming a shim of a delivery valve spring. CONSTITUTION:A movable iron core 20 is placed slidably between a circular end face 151 of a delivery valve holder facing with one end of a delivery valve spring 14 to be contained in a delivery valve holder 15 and one end of a delivery valve spring 14. An electromagnetic coil 19 is wound over a fixed iron core 18 to magnetize it. Under heavy load, power is fed to said coil 19 by means of a rack position signal to attract the movable iron core 20 toward the fixed iron core thus to move downward. Consequently under heavy load, the delivery valve spring fixing force or delivery valve opening pressure will increase to reduce effective unload under low speed region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a jerk type fuel injection pump having an rJ variable suction and discharge valve.

Figure 1 shows a cross section of a conventional fuel injection pump.

A cross section of the variable suction/return discharge valve is shown in FIG. In the figure,
01 is the fuel cam, 02 is the cam roller, 03 is the pump spring, 04 is the rack for controlling the injection amount, 0 (3 is the plant gear,
The fuel cam 01 reciprocates within the plant barrel 07, and the injection amount control rack 04 rotates around the axis. 05 is the oil supply hole.

08 is an oil drain hole, both of which are provided in the plunger barrel. 09 is the 70-lantern chamber, a space surrounded by the top surface of the plunger barrel 06 and the plunger barrel 07.

010 is a fuel injection pump main body, and 011 is a variable suction/return discharge valve, which is located above the plunger chamber 09.

Piston part 012 and discharge valve guide 0 that define the amount of suction back
A gap is provided between 13 and 13. 014 is a discharge valve spring,
015 is the discharge valve holder, 016 is) 0 run gloss lead,
017 is the splint 1 injection pipe.

When the plunger 06 is raised by the rotation of the fuel cam O1, the oil supply hole 05 and the oil drain hole 08 are gradually closed, and the oil pressure in the plunger chamber 09 is raised.

If this oil pressure becomes larger than the sum of the seedling pressure in the fuel injection pipe 017 and the spring force of the discharge valve spring 014.

Press the variable suction and discharge valve (l l l constant) to start discharging fuel.After the oil supply hole 05 and oil drain hole 08 are closed, the plantars 06 are arranged in two rows, and the plantars reed 016 are opened. If the oil drain hole O8 is clogged, oil draining will occur,
The oil pressure in the Cyrano gloss chamber 09 decreases.

Furthermore, if the oil drain hole 08 opens I'', the discharge speed V of the fuel 11
, becomes O, and if the variable suction and return discharge valve 011 descends, the discharge speed becomes negative, and the suction and return action of O.1 occurs. Here, the fuel amount (ΔQOst "" 4 d-tc is defined by the suction collar length tc and the inner diameter d of the valve guide 013 shown in FIG. 3(a) is the geometric suction return amount. Therefore, the amount of fuel Δq defined by the moving 11jlFA from the time when the discharge speed v1) = 0 until the valve is seated is called d2·z4−effective suction return amount. In the variable suction-back discharge valve, a gap is provided between the piston part ( ) 12 and the valve guide 013, but in the high-speed rotation range, the valve lift becomes large due to the throttling effect of the gap Q.
Due to the inertia of the valve, the discharge speed decreases to 0.The amount of descent of the valve in the groove is small, so the valve lift of the discharge material is large, and the amount of lift is about the same as a normal discharge valve without a gap. becomes. On the other hand, in a low speed rotation range, the throttling effect due to the gap is small, and the lift of the variable suction and discharge valve becomes small. This is the third in total
As shown in the figure. Also.

To control the amount of fuel to be discharged, the injection amount control rack 0/I rotates the plant gear 06, and the reeds 01G and 4-1
This is done by changing the relative position with the oil hole 08.

However, the above method has the following drawbacks.

Keep the injection amount control rack 040 position 14 constant.

, the effective suction return M when changing the IF71 rotation speed,
The characteristics are shown in Figure 4 for low load and high load. As mentioned above, the valve lift of the discharge material of the variable suction-back discharge valve is generally small in the low-speed rotation range, and large in the high-speed rotation range.
Since the valve lift amount of the 1st discharge material corresponds to the 1st effective suction back amount, the effective suction back clearance is large in the high mountain rotation range, and the 4T effective suction back amount decreases as the rotation speed decreases. The speed range in which the suction-back jf changes varies depending on the load, and as shown by the solid line in Fig. 1 (1)), the effective suction-back amount is large in the high load range, even down to the low level 1.For this reason,
The injection quantity characteristics of the Rakku-N device are as shown in Figure 5, and the normal discharge without gaps (indicated by the branch line in the figure)
On the other hand, it is possible to improve the sudden drop in the injection amount in the low speed rotation range under low load (indicated by Rcl), but not so much at high load (indicated by Rc2).

Therefore, when using the tOj suction and discharge valve, the safety of engine idling in the low speed and low load range is improved, but
When the load increases at low speeds, the stability of the engine speed control deteriorates.

In order to improve this, it is necessary to maintain the injection characteristics in the low load range and to improve the drop in the injection amount in the low speed range in the high load range, as shown by the dashed line in FIG. As shown by the dotted line in Fig. 4(b), there is an effective suction m-
It is necessary to move the rotational speed, which begins to decrease, to a high speed. To solve this problem, it is effective to increase the spring force of the discharge valve spring that presses the variable suction and discharge valve, but in that case, the injection quantity characteristics in the high load range will not be improved. Ruga.

On the other hand, there are disadvantages in that the injection quantity characteristics worsen in the low load range, causing a sudden drop in the injection quantity in the low speed range.

The purpose of the present invention is to focus on the above-mentioned points, and to provide an nJ variable suction/return discharge valve that maintains the effect of the conventional variable suction/return discharge -JR in the low load range and improves the decrease in fuel injection amount in the low speed/high load range. The purpose of the present invention is to provide a fuel injection pump having a +q pump, and its feature is that in a Noyak-type fuel injection pump 0 having a variable suction and discharge valve, a discharge valve spring is housed, and one end side of the spring is opposed to the other. a plate-shaped movable iron core that is slidably interposed between one end of the spring and the inner end surface and compresses the spring; A fixed iron core protrudes from the inner circumferential surface of the discharge valve holder at an interval of 1, and an electromagnetic coil provided on the discharge valve holder to excite the fixed iron core.

In this case, by energizing the fixed iron core, the iiJ moving iron core that forms the 7mm of the discharge valve spring is sucked! load 2
The opening pressure of the variable suction/return discharge valve can be changed depending on operating conditions such as rotational speed.

In other words, in the low speed and high load range of the two engines, suctioning the driving iron core increases the valve opening pressure of the discharge valve, improving the speed control stability of Iso 1\1 over a wide range of both high load and low load. be done.

An embodiment according to the present invention will be described below with reference to FIG. 1fi1.

FIG. 6 is a sectional view showing a discharge valve boulder equipped with an apparatus according to an embodiment of the present invention.

The present invention relates to components within a discharge valve holder, which will be described below. The other parts are the same as the conventional ones.

That is, numbers 1 to 17 are shown in FIG. 1 (1) showing the conventional example.
It is the same as 0174 from 1.

20 is a shim, which is housed in the discharge valve boulder 15;
A plate-shaped pJ moving iron core is interposed in a sliding pj between the inner end 15.1 of the discharge valve boulder and the - end of the discharge valve spring, which is opposed by the Shode Ispring 14. It is.

A fixed iron core 18 is provided protruding from the inner peripheral surface of the discharge valve holder 5 at a distance from the shim 20 in the direction of the yoke.

Reference numeral 19 denotes an electromagnetic coil, which is disposed around the outer periphery of the fixed iron core 18 and magnetizes the fixed iron core 18.

21-J: Terminal, which is the end A of the electric circuit connected to the electromagnetic coil 19.

” - We will discuss the effect in the case of the following configuration.

The basic operation regarding the discharge of fuel H is the same as that of the conventional type, and the suction and return operation of the fuel H will be described below.

The electromagnetic coil 19 is connected to a control unit (not shown) through a terminal 21, and receives a signal 2 related to the load on the control unit, such as a rack 4 for controlling the injection amount.
1 beach is detected and this signal is input. In the case of low load (as shown by rack position R81), the electromagnetic coil 19 is not energized and the shim 20 is connected to the discharge valve bone 1/
The force of the discharge valve spring is the same as that of the conventional one. The return action is the same as the conventional one, and the change in the effective suction return amount with respect to the pump rotation speed is the same as the conventional one.On the other hand, in the case of high load (indicated by rack position Rc2), the rack position The electromagnetic coil I9 is energized by the signal 11<L, and the shim 20 is attracted to the fixed iron core and moves downward in FIG.

Therefore, in the high load range, the force of the discharge valve spring extension, that is, the discharge valve opening pressure, becomes higher than that of the conventional one, as shown in Fig. area is reduced compared to the conventional one.

If we summarize the above characteristics regarding the pump rotation speed of the effective suction back meter, we get the following equation.

(1) In the high load range, the effective sucking back amount in the low speed range is reduced compared to the conventional one. In the high speed range, it has the same characteristics as the conventional one. (2) In the low load range, it has the same characteristics as the conventional one.

The above case has the following effects.

(1) In the high load range, the effective suction amount in the low speed rotation range decreases as described above, so the sudden drop in injection rate in the low speed high load range is improved, as shown by the solid line in Figure 9. The injection amount characteristics are as follows.

(2) In the low load range, as mentioned above, the conventional effective suction and fine movement is maintained, so as shown in Figure 9, the conventional variable The injection amount characteristics of the suction and discharge valve are maintained.

(3) As a result, the regulating stability of the engine is improved over a wide load range from low load to high load in the low speed rotation region.

Note that 1 and above change the action of the pJ variable suction return discharge valve to rJ change depending on the load, but for other Id light conditions, the action may be changed to riJ depending on the rotation speed, 〃1h degree, etc. In contrast, the injection amount characteristics are improved and similar effects can be obtained.

[Brief explanation of drawings]

Figure 1 shows a conventional single fuel injection system with a variable suction and discharge valve.
+5 sectional view showing the pump, Figure 2 is a sectional view showing the variable suction return discharge valve, Figure 3 (a) P (b) + (+1 shows the difference in lift of the variable suction return discharge valve depending on the pump rotation speed Figures 4 (a) and (b) are diagrams showing the effective suction-back timing performance at low and high loads using the il-i variable suction-back discharge valve; Figure 5 is a diagram showing the A diagram showing the injection amount characteristics at low load and high load when a suction discharge valve is used; FIG. 6 is a sectional view showing a discharge valve holder equipped with an embodiment of the device according to the present invention; FIG. 8 is a line diagram showing changes in the opening pressure of the variable suction and discharge valve due to load; FIG. The figure is a diagram showing fuel injection suspension 111i properties. 11...FjJ variable suction and return discharge valve, lll...discharge valve spring. I5...discharge valve holder, 18...fixed iron core , 19・
...Electromagnetic coil, 20..."J moving iron core. 1st figure 2nd figure (θ) J!1ch1y in D upper $ (t))
i'i*J% total a1i'l (C) I Ujitake's m
Combined VD above 111 needle grapes last 3g! r's valve riff 1, Hiiragi) Gin's non-den〕masu]・3 Kanborep concave rotation number Np (b) Straw anger letter d) case Bo) Fu・talk back father xp (a) Mr. I゛Sharifukugi・No Tsuki Raito Fang 4 figure / l = 5 evil O 6 figure PCI RC2 Lucky standing off factor, t0 nf 0 number of mouths up Fang 8 figure 剌bonobu times 10 buff Np ''＞q figure procedural amendment ( (Spontaneous) January 29, 1980 Director-General of the Japan Patent Office -1 Kazuo Sugi 1. Indication of the case 1988 Patent Application No. J7/1060 2 Title of the invention Relationship to the case Patent applicant address: 2-5-1 Kuunouchi, Chiyoda-ku, Tokyo Name (620) Mitsubishi Heavy Industries, Ltd. 4 Sub-agent Address: 12-12 Fujiba, Kohoku-ku, Yokohama, 222
No. 24, No. 5, Detailed Description of the Invention of Part 1, Column 6, the contents of the amendment are amended as d2 and lc. (2) Add "certain J" next to FmJ on page 5, line 1 of the same page.
711) Correct. (49, page 5, line 10, after “injection j at...”
Add "Quantity". (5) The word “electrical circuit” on page 8, line 3 is r +! ff
l road” and sleeves. Play IE. Procedural amendment () 0 1981: U Month 15 Mr. Illuo Yoiwakasugi, Director of the Japan Patent Office Indication of the case 1982 Patent application No. 17 /l 060 = 2 Name of the invention Fuel injection, 19nno 0 3, Relationship with the case of the person making the amendment Patent applicant address Chiyo, Tokyo [2-5-1, 90-nai, 11-ku Name (620) Mitsubishi Heavy Industries, Ltd. 4 Sub-agent 1 5 Date of amendment order
---February 2, 1982 (shipment date 58.2.22)
)6 Contents of the amendment (1) Revision of the invention in the detailed description, 4F of the #lII explanation
l□l and Figures 3 and 11 of the drawings. (2) Shown in Figure 1, line 3, page 11 of the specification. "and"
In addition, the following sentence is added between ". ``In other words, Fig. 3(a) shows the pushed up state during dispensing;
(b) is the valve lift at the end of discharge 11'1 in the case of high speed;
(c) shows the end of discharge at low speed (H,, jr of J1'
Each lift is shown. (3) Shown in Figure 11, page 4, line 11. ” and “before” add the following sentence. [i.e., the 41st macro a) is a low-load "equipment," (1))
indicates the case of madder ↑d〒, respectively. (4) Figure No. 3 of the drawings shall be amended as per the attachment. (5) Attach Figure 4 of the drawings (=1 amended as per attached sheet. 7 List of attached documents (1) Drawing 2
Leaf + (2J tb)
+C+71-3 Pump (b) Bonpro t (71

Claims (1)

[Scope of Claims] 1. In a jerk-type fuel injection pump having a variable suction-back discharge valve, one end of the spring of a discharge valve holder that houses a discharge valve spring and forms an inner end surface that faces one end of the spring; A plate-shaped movable iron core is slidably interposed between the inner end surface and compresses the spring. A fixed iron core protruding from the inner circumferential surface of the discharge valve holder at an axial distance from the moving iron core, and an electromagnetic coil provided on the discharge valve holder to excite the fixed iron core. Fuel injection, I? pump.