JPH02188665A - Fuel injection pump for internal combustion engine - Google Patents

Abstract

PURPOSE: To correctly measure fuel quantity with a simple structure by connecting a fuel supply passage that is connected to extrusion chamber of a feed pump with the way between an electronic control valve and a fuel pool, while arranging the electronic control valve in the way of fuel supply passage that connects a pump working chamber to the fuel pool. CONSTITUTION: A radial piston injection pump has a pump piston 3 that works in combination with a cam ring 14 to reciprocate, and it supplies the fuel pressurized in the pump working chamber 5 to an injection valve 33 through a feed pipe 32 with a distributor 2. The not injected remainder fuel is guided to a fuel pool 16 built in a movable wall 17 through a fuel passage 15 attached with an electronic control device valve 21. In this case, a fuel supply passage 29 is branched and connected to the way between the electronic control device valve 21 and the fuel pool 16 in the passage 15, and the other end of the passage 29 is connected to extrusion chamber 26 of a feed pump 23. While the movable wall 17 of the fuel pool 16 opens a load reducing hole 19, a one way valve 30 is opened to supply the fuel to the pump working chamber 5.

Description

DETAILED DESCRIPTION OF THE INVENTION CPI INDUSTRIAL APPLICATION The present invention provides a fuel injection pump with at least one pump working chamber closed by a pump piston within a part of the casing of the fuel injection pump. , the plate Ponzo working chamber is connected to the fuel reservoir via the fuel passage τ, and the fuel reservoir is movable against the spring force of the ark.
A control member is disposed within the fuel passage, and the control member connects the pump working chamber and the fuel reservoir at the end of high-pressure injection during the feed stroke of the pump piston. The connection is controlled so that this connection is broken before the pump piston's feed stroke for injection starts, and the pump operation chamber is connected to the fuel storage chamber during the pump piston's light stroke. It relates to a type that is provided with a connecting fuel supply passage.

[Conventional technology]

In this type of fuel injection pump known from specification DW-086518266, compressed fuel from the ponzo cylinder is supplied to the fuel tank in an amount exceeding the required injection amount. , this excess fuel quantity must be returned to the bonnet working tank until the intake stroke begins. The fuel reservoir is exposed to high pressure by directly receiving the reduction control load until it is emptied. Therefore, the fuel tank must be designed to be tall, which causes problems regarding sealing performance.Depending on the rotational speed of the internal combustion engine, the load condition of the fuel reservoir varies depending on the rotation speed of the internal combustion engine, and the possibility of compressing the fuel reservoir volume. Inaccuracies occur in the connection between the fuel sump and the pump working chamber, and thus it is not guaranteed that all the reduced fuel is guided back into the pump working chamber even at high engine speeds. The control takes place via a control edge formed by an annular groove and a longitudinal groove provided in the pump piston. However, these annular grooves and the longitudinal direction t4 have a system drawback in that the uncontrolled fuel volume present in them becomes a dead volume.

All that has been said above makes it difficult to accurately meter the amount of fuel to be injected, especially in rapid load changes, and thus to increase the efficiency of the internal combustion engine by increasing the number of strokes. Gives a shadow n. In addition, the provision of additional features on the pump piston requires costly work steps and i1i control membrane control, in which adjustment ifr deviations due to wear have a negative impact on the efficient operation of the fuel injection pump.

[Problem of invention]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to eliminate the drawbacks of the known fuel injection pumps.

[Means to solve the problem]

According to the present invention that solves this problem, the control member
In the 1+ control valve, the electronic 1lJIJ control valve is disposed within the fuel passage, and a fuel supply passage opens in the fuel passage at a position between the electronic control valve and the fuel tank. ,
The movable wall of the fuel reservoir opens the negative Oi reduction hole from a predetermined stroke, and at the same time, the feed pump is pushed back to operate the member in the direction of the dazzling stroke, and the retraction of the feed pump is to move the member back. The fuel supply passage is branched from the fuel supply passage.

〔effect〕

The fuel injection pump according to the invention has the advantage that the fuel supply to the pump working chamber can be controlled by a simple device. With this system, there is no requirement to use a pump piston to act as a TIIIJ control member for controlling and distributing the entire flow of fuel to and from the pump chamber. The device according to the invention essentially consists of a feed pump, which operates according to the retraction principle, and an electronic control valve, which acts as a control element. As a feed pump, it reduces the pressure to a limited level. % small glare t-
pump is used. This saves the construction costs of the parts in operational connection with the pump and eliminates problems with sealing. Such simple parts are manufactured at low cost. In addition, the basic equipment can be directly controlled w, m
The economic advantage is increased by the possibility of omitting integrated valves in the device according to the invention, since it can be added to various systems with cells.

'Fuel quantity control by means of the E/JBLJ control valve allows precise injection quantity control, since the backflow light rate in the pump working chamber is released on the basis of the variable fuel sump backflow. .

Advantageous variants and improvements of the fuel injection pump according to claim 1 are possible with the measures specified in the other claims. It was constructed as a stepped stone. The retraction of the feed pump is controlled such that the part is pushed back towards the device by the pump piston during the preceding movement process between the end of the feed and the moment of reversal in the uppermost movement position of the pump piston during the light transfer process. It is configured in such a way that a larger amount of fuel than fuel can be supplied to the pump chamber, which allows the pump chamber to be filled more quickly and improves the xD of the internal combustion engine.
A high drive rotation speed can be obtained.

〔Example〕

Next, the configuration of the present invention will be specifically explained with reference to the embodiments shown in the drawings.

A rotating distributor 2 is disposed in the Cousing of a distribution type radial piston injection pump, and the distributor 2 includes:
In contrast, the fuel is pumped via a number of pump pistons which are guided in stationary bearings located radially.
Ru. First, the pump piston 3 will be explained in detail. An annular groove 4 is provided in the distributor 2 in the plane of movement of the pump piston 3 . This ring m4 is connected to a pump working chamber 5, the volume of which can be changed periodically by an axially movable pump piston 3. The pump piston 3 is seated in a sealed and movable manner in a bore 6 of the stationary piston holder 1, which extends radially with respect to the distributor 2. A crank-shaped spring receiver 9 engages in an annular groove 8 formed on the opposite side of the pump working chamber 5 of the pump piston 3 . One end of the piston return spring 10 acts on the bottom of the spring receiver 9, and the other end acts on the annular 611 of the piston holder T.
It is supported by 19. Rotating rod shaped like a forest °
12 concentrically surrounds the giston return spring 10, and the cylindrical circumferential wall of the rotary rod 12 likewise projects into the annular groove 11, furthermore the rotary rod 12 has an inner bottom surface thereof. , on the opposite side of the piston return spring 10,
It forms a bearing surface for the bottom of the spring receiver 9.

The outer bottom surface of the rotating rod 12 is connected to the piston return spring 10.
It is connected to the roller 13 by four frictions by the spring force. This row 213 is connected to the cam ring 14 which is driven synchronously with the distributor 2.
By means of the inwardly directed cams of this cam ring 14, the pump piston 3 performs a stroke movement in the direction of reducing the pump working chamber 5, against the direction of action of the piston return spring 100.

In the embodiment shown in FIG. 2, the fuel supply and the removal of the uninjected surplus fuel quantity from the pump work chamber 5 take place via a fuel channel 15 opening into a fuel reservoir 16. The fuel reservoir 16 has a movable wall 17, which movable wall 11 is adjustable against the spring force of a spring 18.
From a predetermined stroke, the load reduction hole 19 forming an annular groove is opened 1UIJ, and this negative fI reduction hole 19 is connected to the suction chamber 20 of the fuel injection pump, and the suction chamber 2υ is not shown. Maintained at low pressure via pre-feed pump.

An electronic control valve 21 is interposed within the fuel passage 15 .

The movable wall 1T of the fuel tank 16 displaces the smaller diameter portion of the stepped piston 22 during its stroke movement.

This portion is sealed against the fuel reservoir 16 and is slidably supported in a portion of the stepped hole 51. The larger diameter portion of the stepped piston 22 forms a retractable member 24 within the feed pump 23 . This retraction member 24 is formed in an annular surface between the larger diameter portion and the smaller diameter portion of the stepped piston 22. Beveled hole 5
A recess formed as a fuel gauge=W in part with another part of 1 limits the display 26. The push-back position 26 is the suction chamber 2
It has suction 4'#27 leading to u. A first check valve 28 is disposed in the suction conduit 21, and this prevents the flow of air from the chamber 26 to the suction chamber 20. For retraction, a fuel supply passage 29 branches off from the chamber 26. This fuel supply passage 29 has a second check valve 30, and this m2 check valve 30 is retracted from the chamber 26 in the fuel passage 15 between the fuel reservoir 16 and the electronic control valve 21. A distribution groove 31 formed in the outer peripheral surface of the distributor 2 extends from the pump working chamber 5 .

Through this distribution groove 31, when the distributor 2 rotates, a feed conduit 32 is successively connected to the Bonzo cooking chamber 5 during the feeding stroke of the bonder Cstone 3. Feed conduit 3
2 (only one is shown) are distributed around the circumference of the hole 340 that guides the distributor 2, depending on the number of cylinders to be supplied of the internal combustion engine to which it belongs; Negative # light M valve (not shown) and one injection each 9e33 and t
have.

The working style of the fuel injection pump shown in FIG. 1 will be explained below with reference to FIG. 2 and wJ6. In Figure 3,
Starting from the lowest movement position of the pump piston 3 at UT, the lifting and lowering movement curve of the pump piston 3 is shown over the entire rotational angle. This pump piston 3 has a point tFB (after the pre-stroke hv and the fuel passage 15
After the valve 21 is closed at the start of pressure feeding, high-pressure pressure feeding is started. This high-pressure feeding is carried out after the stroke hN)
At B+ (completion of pressure feeding), the process is terminated as follows.

In other words, the valve 21, which is in the closed position only during the injection period from FB to Fg''1 (point), and which shuts off the fuel passage 15, opens, thereby allowing the pump working chamber 5 under high pressure to open the fuel passage 15. Negative frm to lower pressure level through
As a result, the pressure in the pump working chamber 5 drops under the pressure required to keep the injection valve 33 open for injection. Point) From IFK until the pump piston 3 moves in reverse at top dead center OT, the amount of fuel that is compressed by the pump piston 3 but not injected is
5 to the fuel reservoir 16.

The light in the fuel reservoir 16 has already started in the previous stroke hv,
It is interrupted in the closed position M of the valve 21. Fuel reservoir 1
6 The moving speed Jjh of the movable wall 17 limited to t-fbfj is
Yes, 1 nJ is carried out until the pressure acting on the wall 17 and the return force of the spring 18 produced by the movement of the movable wall 170 are balanced. When the amount of fuel supplied to the fuel reservoir 16 exceeds a predetermined amount, the movable wall 17 reaches the load relief hole 19.

This load relief hole 19 opens the connection from the working chamber 5 to the suction chamber 20 present in the fuel injection pump (the pressure level in this suction chamber 20 is relatively low). This 7'L limits the pressure rise in the fuel reservoir 16, and at the same time, the raised and lowered movement of the movable wall 11 causes the stepped piston 22 to be
is caused to undergo displacement movement. At this time, piston 2 with crotch
The push-back of 2 and the push-back of 25 increase the volume of the volume 26, and this push-back also lowers the pressure level of 26 yen and the pressure level of 20 yen of the suction chamber. This pressure difference is caused by the first check valve 28
and the displacement through the first check valve 28 from the fuel tank 2u, which is under low pressure by the pre-feed pump, is compensated for by opening the flow of fuel into the trough 26. . By the suction stroke of the pump piston 3 between OT and UT and by the opened valve 21, a reversal movement of the movable wall 17 is carried out, assisted by the return force of the spring 18. As a result, the movable wall 1T valves the fuel passage 15 again to send the fuel volume of 16 yen to the pump working chamber 5, and when the pump working chamber 5 is refilled, the compression stage after the top dead center OT is reached. is started. At the same time, by emptying the fuel tank 16, the reverse transmission % of the stepped piston 22! Fuel is irradiated into the pump working chamber 5 with the aid of the EIIK. At this time, the retraction of the corrugated piston 22 causes the surface 25 to additionally release the fuel against the now closed tenth stop box 28, opening the fuel supply passage located at 19° in the flow direction. Via the second check valve 30, the fuel is fed into the 15 yen fuel passage leading to the pump working chamber 5 until the pump working chamber 5 is completely filled.

With such a configuration, the pump working chamber 5 can be quickly filled with fuel at a relatively high and constant filling pressure,
Even at high rotational speeds of the internal combustion engine, a sufficient fuel injection quantity is provided for the compression phase of the pump piston 3, and control of the fuel supply of the pump working chamber 5 is obtained via the adjustable valve 21.

[Brief explanation of the drawing]

Figure 1 is a partially reduced cross-sectional view of the Lano Algiston pump.
FIG. 2 is a schematic diagram of a fuel injection pump according to an embodiment of the invention, and FIG. 6 is a graph showing the movement of the pump piston. 2... Distributor, 3... Pump piston, 4... Block groove, 5... Pump working chamber, 6... Hole, 1... Piston holder, 8... Block groove, 9... Spring receiver, 1
u... Piston return spring, 11... Block r4.12
...Rotating rod, 13...Roller, 14...Cam ring, 15...Fuel passage, 16...Fuel reservoir, 1
7... Movable wall, 18... Spring, 19... Load@passage, 20... Suction chamber, 21... Electronic control valve, 22
...Stepped piston, 23...Feed pump, 2
4... Pushing back is a member, 25... Pushing back is a surface, 26...
Push-back chamber, 21... Suction conduit, 28... Check valve,
29... Fuel supply passage, 30... Check valve, 31...
・Distribution + f4.32... Feed conduit, 33... Injection valve, 34... Hole, 51... Stepped hole 3... Pump piston 5... Pump working chamber 15... Fuel passage

Claims (1)

[Claims] 1. A fuel injection pump having at least one pump working chamber (5) closed by a pump piston (3) in a part of the casing of the fuel injection pump, the pump working chamber (5) containing fuel. It is connected via a passageway (15) to a fuel reservoir (16), which fuel reservoir (16) has a movable wall (11) movable against the spring force of a spring (18), said Fuel passage (1
5) A control member is arranged in a circle, and the control member connects the pump working chamber (5) and the fuel reservoir (16) at the end of high-pressure injection during the feed stroke of the pump piston (3), and The connection is controlled to be cut off before the start of the feed stroke for injection of the piston (3), and the pump working chamber (5) is connected to the fuel storage chamber during the filling stroke of the pump piston (3). fuel supply passage (2
9), the control member is an electronic control valve (21), and the control member is an electronic control valve (21).
) are arranged in a circle in the fuel passage (15), and the electronic control valve (21) and the fuel reservoir (16) in the fuel passage (15) are arranged in a circle.
), and the movable wall (17) of the fuel reservoir (16) controls the opening of the load reduction hole (19) from a predetermined stroke, and at the same time the feed pump The displacement member (24) of (23) is operated in the direction of the suction stroke, and the fuel supply passage (29) is branched from the displacement chamber (26) of the displacement member (24). A fuel injection pump for an internal combustion engine. 2. The movable wall (11) is constituted by the end face of the smaller diameter part of the stepped piston (22) which is slidable in the stepped hole (51), and the displacement member (24) is displacement constituted by the larger diameter part of the stepped piston (22) and formed by an annular surface between the larger diameter part and the smaller diameter part of the stepped piston (22); Face (25)
, the displacement surface (25) delimiting a fuel storage chamber formed as a displacement space (26),
The fuel injection pump according to claim 1. 3. the suction conduit (27) of the feed pump (23) is supplied with fuel by the pre-feed pump via a first check valve (28) having a suction chamber (20) arranged in the fuel injection pump; 3. The fuel injection pump according to claim 2, wherein the displacement chamber (26) of the feed pump (23) is connected to the fuel supply passage (29) via a second check valve (30).