JPS60147544A - Distributor type fuel injection pump - Google Patents

Abstract

PURPOSE:To reduce the size of a distributor type fuel injection pump and to simplify the structure of the same, by providing a high-speed solenoid valve in a passage communicating a fuel chamber of the pump and a high-pressure chamber the volume of which is varied with reciprocating motion of a plunger, and controlling said high- speed solenoid valve by a control means attached to the pump in a unitary manner. CONSTITUTION:In a fuel injection pump 1 shown in the drawing, a plunger 10 is reciprocated with rotation by a cam disk 11 that is kept in sliding contact with a roller 6, along with rotation of a driving shaft 3 turned synchronously with rotation of an engine, whereby fuel drawn from a fuel chamber 30 into a high-pressure chamber 18 via a high-speed solenoid valve 19 is pressurized and delivered to a plurality of injection valves via passages 10a, 10b, 9c and a delivery valve 16. An electronic control means 38 is disposed in a case 27 which is fixed to the upper surface of a pump housing 1 hermetically for defining the fuel chamber 30, so that the control means 38 can be cooled by fuel. Arrangement is such that the high-speed solenoid valve 19 is controlled on the basis of the fuel injection timing and the injection quantity of fuel calculated by the electronic control means 38 from the signals representing the operational conditions of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distribution type fuel injection pump, and more particularly to a distribution type fuel injection pump that is smaller in size and has a simpler structure.

The so-called electronic control that electrically controls the injection amount and injection timing of a distribution type fuel injection pump is disclosed in, for example, Japanese Patent Laid-Open No. 55-57658.
There is something described in the No. This is configured to control the injection amount by driving the control sleeve with a rotary solenoid, and control the injection timing by regulating the pressure on the high pressure side of the timer piston of the timer mechanism with a solenoid valve. This fuel injection pump does not require a governor part compared to a mechanical type that mechanically controls injection timing, etc., and therefore has fewer components, but on the other hand, it requires various sensors and control units, so the overall There was a problem that the manufacturing cost increased.

In order to solve this problem, a distribution type fuel injection pump has been proposed that eliminates the governor and timer mechanism and controls the injection amount and injection timing by opening and closing control of a solenoid valve (Japanese Patent Laid-Open No. 1983-1991).
-91.366). This is done by placing a solenoid valve in the middle of the passage that supplies fuel from the pump to the high pressure chamber defined on the plunger head side.

The injection amount and injection timing are controlled by controlling the opening and closing of this electromagnetic valve. However, when the injection pump pumps high-pressure fuel to the lateral upward injection valve, the high-pressure fuel pressure acts in the opening direction of the solenoid valve, so the valve of the solenoid valve closes against this fuel pressure. It is necessary to set a strong spring force to press the body to close the valve, and accordingly, when opening the valve, a large magnetic force is required to resist the spring force and open the valve body. As a result, there is a problem that the solenoid valve inevitably becomes larger.

The present invention has been made in view of the above points, and eliminates the control sleeve and hydraulic timer, controls the injection amount and injection timing by controlling the opening and closing of a solenoid valve, and reduces the driving force of the solenoid valve. It is an object of the present invention to provide a compact and simple structure by integrally attaching a control device for the electromagnetic valve to an injection pump. In order to achieve this object, in the present invention, a plunger that rotates and reciprocates in relation to the rotation of the engine compresses fuel to be drawn into a high pressure chamber defined at the end of the plunger, and In a distribution type fuel injection pump that distributes to cylinders, a fuel chamber is provided integrally with a pump housing of the injection pump and is filled with fuel pumped from a feed pump driven in relation to the rotation of the engine; a spool-type high-speed solenoid valve mounted on the pump housing to open and close a passage communicating between the fuel chamber and the high pressure chamber; a detection means for detecting the operating state of the engine and outputting a corresponding signal; The present invention provides a distribution type fuel injection pump comprising: an electronic control device disposed in the fuel injection pump for controlling the high-speed electromagnetic valve by calculating the fuel injection timing and injection amount based on the signal indicating the operating state.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a longitudinal cross-sectional view of a distribution type fuel injection pump to which the present invention is applied, in which a drive shaft 3 is rotatably supported in a pump housing 1, and one end of the drive shaft 3 is connected to the output shaft of the engine. A foot pump 4 is attached to suck and pressurize fuel from a fuel tank (neither of which is shown), and pump it into a fuel chamber 30 (to be described later), and a plurality of rollers 6 are rotatable radially at predetermined intervals on the outside of the end. A roller holder 7 is loosely fitted between the feed pump 4 and the roller holder 7, and between the feed pump 4 and the roller holder 7 is a toothed gear-shaped tire 8 having a predetermined number of protrusions protruding from its circumferential surface at predetermined intervals. It is fixed.

The suction port 4a of the feed pump 4 is communicated with a joint 5 fixed to the upper surface of the housing 1 through a passage 1a formed in the housing 1, and the inlet side mouthpiece 58 of the joint 5 is connected through an oil path (not shown). and connected to the fuel tank.

A discharge port 4b of the feed pump 4 is communicated with an upper portion of one side of the fuel chamber 30 via a passage 1b formed in the housing 1 and an oil passage 28 connected to the passage.

A lid body 2 fixed to the end of the pump housing 1 on the side opposite to the drive shaft
One end of a plunger 10, which reciprocates and rotates to suction and pressurize and distribute fuel oil, is slidably and liquid-tightly fitted into a plunger barrel 9, which is installed in alignment with the drive shaft 3, and the other end is connected to one end of the drive shaft 3 via a driving disk, and a cam disk 11 is fixed to the end. The cam disk 11 is interposed between a spring seat 12 that presses against each roller 6 of the roller holder 7 via a cam surface, a spring seat 12 that presses against the cam disk 11 via a shim, and the opposite end surface of the housing 1, and is located outside the plunger 10. It is pressed into contact with a plurality of plunger springs 13 arranged at.

An overflow valve 15 is screwed into a hole 2a formed in the upper surface of the lid 2, and an outlet side mouthpiece 15a of the overflow valve 15 is connected to a low pressure side of the pump, such as the fuel tank, through an oil passage (not shown). One end of a passage 2b bored in the upper surface of the lid body 2 and near the hole 2a opens to the inner peripheral surface of the lower part of the hole 2a,
The other end communicates with the lower part of the other side of the fuel chamber 30 via an oil passage 29 . Also.

The one end of the passage 2b communicates with an annular groove 9b formed at the end of the inner peripheral surface of the plunger barrel 9 through passages 2c and 9a formed in the lid 2 and the plunger barrel 9.

Vertical hole 10 bored in the axis of the end face of the plunger 10
The lower part of a is bored in the radial direction and communicates with a distribution boat JOb that opens on the circumferential surface, and the open end of this distribution port]Ob is bored in the plunger barrel 9 at equal intervals radially in accordance with the number of cylinders. It communicates with each passage 9c according to the rotation. Each of these passages 9c communicates with one end of each passage 2d formed radially at equal intervals in correspondence with the number of cylinders in the lid body 2, and a delivery valve 16 is installed in each of these passages 2d. Each of these delivery valves 16 is connected to a corresponding injection valve (both not shown) of the engine via an oil passage.

A head plug 17 is fluid-tightly disposed in the lid body 2 with the plunger barrel 9, and the end face of the head plug 17, the inner peripheral surface of the plunger barrel 9, and the plunger 1
A high-pressure chamber 18 is defined between the end face of 0 and 0. This head plug 17 is provided concentrically with a screw hole 17a that matches the plunger 10 and a screw hole with a larger diameter than the screw hole 17a, and one end of the case 20 of the high-speed solenoid valve 19 is installed in the screw hole 17b. The solenoid valve 19 is screwed into the hole 17a in a liquid-tight manner.
A spool 21 is inserted liquid-tightly and slidably in the axial direction.

The spool 21 of the electromagnetic valve 19 is loosely fitted into a coil 22 housed in a case 20, and an annular groove 21 is formed on the outer circumferential surface of the end projecting outside the case 18. An opening hole 21b is provided through the hole 21b. This hole 21
b is for facilitating movement of the spool. A return spring 23 is housed in a hole bored in the end surface of the inner end of the case 19 of the spool 21.
One end is pressed against the end surface of the hole, and the other end is pressed against the opposing end surface of a yoke 24 housed in the end inside the coil 22.

When the coil 22 is energized, the spool 21 is attracted by electromagnetic force against the spring force of the spring, and is drawn into the case 20 until its end face abuts and locks on the yoke 24, and when the coil 22 is deenergized, the return spring 23 It is pushed out by the spring force and its end surface is pressed against the opposite end surface of the hole 17a.

The head plug 17 has one end opening on the inner peripheral surface of the hole 1.7a and facing the annular groove 2+,a of the spool 21 when the solenoid valve I9 is de-energized as shown in the figure. Each other end connects to the hole 2 through the passage 2e formed in the lid body 2.
A passage 17d opening into the high pressure chamber 18 is provided at the bottom of the head plug 17, and one end is a hole in the head plug 17], 7
A passage 17e is formed that opens near the end of a and whose other end communicates with the passage 2e.

When the solenoid valve 19 is deenergized, the passage 17 is
c and 17d are communicated via the annular groove 21a of the spool 21, and in the case of the spool 21, these passages +7c and 17cl
The spool 21 separates the spool from the spool 21.

A fitting 25 is screwed onto the bottom of the pump housing, and the inlet side cap 25a is connected to the engine's lubrication system (both not shown) through an oil passage, and the outlet side 25b is connected to the engine lubrication system (both not shown). Open inward. Furthermore, a joint 26 is attached to the side wall of the pump housing l, and its inlet side is open facing the inside of the pump housing l, and its outlet side is connected to an oil tank (both not shown) through an oil passage. connected to.

The fuel chamber 30 is formed integrally with the pump housing J by liquid-tightly fixing a cylindrical case 27 to the upper surface of the pump housing 1. One end of an oil passage 29 opens at the bottom of the side wall. An electronic control device 38 is housed within this fuel chamber 30.

The rotation sensor 31 detects the rotation speed of the drive shaft 3, that is, the fuel r1 pump, and is disposed on the earthen wall of the pump housing 1, facing the protrusion of the gear-shaped disk 8 at a small distance. The connection terminal is connected to the control equipment 38.

This rotation sensor 31 sequentially detects the projections of the rotating disk 8 and outputs a pulse signal. The temperature sensor 32 is for detecting the temperature of the fuel oil in the fuel oil chamber 30, and is fixed to the inner wall surface of the case 27, and its connection terminal is connected to the electronic control device 38.

The rotation sensor 33 is fixed to the crankshaft of the engine and is disposed opposite to the protrusion of a gear-shaped disk (not shown) having a protrusion corresponding to the top dead center position of each cylinder,
Detects the top dead center position of each cylinder. The temperature sensor 34 is attached to the side wall of the cooling water passage of the engine and detects the temperature of the cooling water of the engine.

The pressure sensor 35 is disposed within the intake pipe of the engine and detects the internal pressure of the intake pipe. The throttle valve opening sensor 36 detects the engine load, and is provided in conjunction with an accelerator pedal (not shown) to detect the rlffi error of the accelerator pedal, that is, the throttle valve opening.

The pressure sensor 37 is connected to the oil passage (
(both not shown) to detect the injection fuel pressure. this! ? , are connected to an electronic control unit 38, respectively. The coil 22 of the high-speed solenoid valve 19 is also connected to the electronic control device 38 .

The electronic control device 38 calculates the fuel injection amount and injection start timing based on each signal input from each sensor 31 to 37 indicating the operating state of the engine, and outputs a solenoid valve drive signal. Advancement or delay in the injection start timing is determined based on a signal indicating the top dead center position of each cylinder inputted from the rotation sensor 33,
The injection amount is corrected based on the deviation between the actual injection amount calculated based on pressure fluctuations during injection inputted from the pressure sensor 37 and the injection amount determined by the calculation.

In such a configuration, in relation to the rotation of the engine, the drive shaft 3
When the feed pump 4 rotates, the feed pump 4 sucks and pressurizes fuel from the fuel tank through an oil passage (not shown), a joint 5, and the passage 1a, and forces the fuel into the fuel chamber 30 through the passage 1h and the oil passage 28, and fills the fuel into the fuel chamber 30. Fill up. fuel chamber 30
The fuel 111 supplied into the tank passes through the oil passage 29 and the passage 2b.
a, 2a, and +7c are filled, and excess fuel is returned to the fuel tank through the overflow pulp 15 and an oil path (not shown). The electronic control device 38 housed within the fuel chamber 30 is cooled by the fuel that is filled into the fuel chamber 30. Since this fuel chamber 30 is located in the path before overflow, a large amount of fuel flows through the fuel chamber 30, and the electronic control device 38 is not effectively cooled.

Further, a part of the oil discharged from an oil pump (not shown) that rotates in conjunction with the rotation of the engine and supplied to each lubricating part of the engine enters the pump housing 1 through an oil path and a joint 25 (not shown). supplied, the pump housing 1
The roller 6, roller holder 7, and camshaft are housed inside. The disk 11° is supplied to the sliding parts of various parts such as the plunger 10 and lubricates these parts. When the liquid level of the oil stored in the pump housing 1 reaches the opening position of the joint 26 (indicated by a broken line), excess oil is returned to the oil tank (not shown) via the joint 26 and an oil path (not shown). . As a result, the oil within the pump housing I is always maintained at a predetermined level.

On the other hand, the electronic control unit 38 outputs a solenoid valve drive signal and supplies it to the high-speed solenoid valve 19 based on the signals input from each of the sensors 3I to 37 indicating the operating state.

When this electromagnetic valve 19 is deenergized, the spool 21 is projected by the spring force of the spring 23 as shown in FIG.
They are communicated via an annular groove 21a. Therefore, drive shaft 3
As the plunger 10 rotates, the plunger 10 retreats toward the cam valve 11, that is, during the suction stroke, fuel is sucked into the high pressure chamber 18 through the passage 17c, the annular groove 21a, and the passage 1.7d.

Next, the plunger 1o moves to the high pressure chamber 18 side, that is, moves to the compression stroke. However, during this compression stroke, as shown in FIG. 2(b), while the electromagnetic flow r19 is deenergized, the passages +7c and 17d are communicated via the annular groove 2]a of the spool 21. As the plunger 10 moves in the compression direction, the fuel in the high pressure chamber 18 flows into the passage 1.
7d, ]7c, and is pushed back to the fuel supply side.

Then, as shown in FIG. 2(b), when the electronic control unit 38 outputs a drive signal to energize the coil 22 of the electromagnetic valve 19 at time t1 of the compression stroke of the plunger, the spool 21 is activated by the spring force of the spring 23. The high pressure chamber 18 and the fuel supply side are shut off by being sucked in against the pressure and closing the passages 17c and 17d.

As a result, the fuel in the high pressure chamber 18 moves through the plunger 1o (
It is compressed together with FIG. 2(a) and becomes high pressure.

This high-pressure fuel is sent under pressure to a corresponding injection valve (both not shown) through a passage, for example, a passage 2d, a delivery valve 16, and an oil passage communicating with the distribution bow hlob of the plunger 1o, and is injected into the cylinder from the injection valve. .

When the electronic control unit 38 stops outputting the drive signal and deenergizes the solenoid valve 19 at time t2 of the compression stroke, the spool 21 protrudes due to the spring force of the spring 23 and enters the passage 17.
c and 17d are connected.

Therefore, the fuel in the high pressure chamber J8 flows through these passages 17d.

17c, and is returned to the fuel supply side, and fuel injection from the injection valve is completed.

Then, as shown in FIGS. 2(a) and (b), the solenoid valve 19
By controlling the energizing time t1, that is, the valve closing timing, the fuel injection timing can be controlled at the optimum timing. Further, by controlling the deenergization time t2 of the electromagnetic valve 19, that is, the valve opening timing, the fuel injection amount can be controlled. That is, the injection start timing is controlled by the activation time t1 of the solenoid valve 19, and the injection amount is controlled by the activation time Δt (=t2 t+') from the activation time t1 of the solenoid valve 19 to the deactivation time t2. .

In addition, during the compression stroke of the plunger 10, high-pressure fuel leaked from the high-pressure chamber 18 to the cam disk 11 side through the space between the plunger 10 and the plunger barrel 9 via the annular groove 9b and passage 9a on the inner peripheral surface of the plunger barrel 9. It is returned to the fuel supply side.

Moreover, the high fuel pressure during fuel injection is applied to the side surface of the spool 21 of the electromagnetic valve 19, and does not act in any way in the axial direction. Therefore, the spring force of the spring 23 for driving the spool 21 is small, and the coil 2
The electromagnetic force of 2 may also be small.

As explained above, according to the present invention, a plunger that rotates and reciprocates in relation to the rotation of an engine compresses fuel to be drawn into a high pressure chamber defined at the end of the plunger, and a fuel chamber filled with fuel pumped from a feed pump that is integrally provided in a pump housing of the injection pump and is driven in relation to the rotation of the engine; a spool-type high-speed solenoid valve that is attached to the housing and opens and closes a passage communicating between the fuel chamber and the high pressure chamber; a detection means that detects the operating state of the engine and outputs a corresponding signal; an electronic control device disposed in the electronic control device for controlling the high-speed solenoid valve by calculating the fuel injection amount and injection amount based on the signal indicating the operating state, and controlling the fuel injection timing and injection amount by the solenoid valve. As a result, the injection timing and injection amount can be controlled at optimal timing according to the operating state of the engine, the fuel oil temperature, etc., and one engine can be operated satisfactorily. In addition, since the injection amount and injection timing can be controlled for each cylinder, it is possible to correct the uneven amount due to variations in the injection system components, etc., and it is possible to reduce the number of cylinders by 4 degrees. It can be done easily.

Furthermore, since the fuel chamber is provided separately and oil is supplied into the pump housing, lubrication with fuel is not required, and a wide variety of fuels can be used. Furthermore, by using a spool-type solenoid valve, high pressure fuel pressure is applied to the side of the spool, so the spring force of the spool return spring can be reduced. Miniaturization becomes possible.

Furthermore, since the electronic control device is housed in the fuel chamber and the second fuel chamber is placed before overflow to increase the amount of fuel passing through, the electronic control device can be effectively cooled. By integrally disposing the electronic control device in the pump housing, errors in assembly and adjustment of the injection pump can be reduced and reliability can be improved.

Furthermore, since a large amount of existing equipment can be used, the manufacturing cost of the injection pump can be reduced, and the injection pump can be supplied at a relatively low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a distributed fuel injection 84 pump to which the present invention is applied, and FIG. 2 is an explanatory diagram of the operation of the injection pump shown in FIG. 1. 1... Bump housing, 4... Feed pump, 7... Roller holder, 9... Plunger barrel. 10... Plunger, 15... Overflow valve. 19...High speed solenoid valve, 31-37...Sensor, 38...
...Electronic control device.

Claims (1)

[Claims] 1. In a distribution type fuel injection pump that compresses fuel drawn into a high pressure chamber defined at the end of the plunger by a plunger that rotates and reciprocates in relation to the rotation of the engine, and distributes it to each cylinder of the engine. a fuel chamber that is integrally provided in the pump housing of the injection pump and is filled with fuel pumped from the phyto-pump that is driven in relation to the rotation of the engine; a spool-type high-speed solenoid valve for opening and closing a passage communicating between the fuel chamber and the high pressure chamber; a detection means for detecting the operating condition of the engine and outputting a corresponding signal; 1. A distribution type fuel injection pump characterized by comprising: an electronic control device that calculates fuel injection timing and injection amount based on signals shown in the figure and controls the high-speed electromagnetic valve.