JPS62276264A - Solenoid valve for overflow of fuel injection pump and method for adjusting injection amount - Google Patents

Abstract

PURPOSE:To provide adjustability for the injection amount according to the load range independently by furnishing a pressing force adjusting means for a spring, which is to apply pressing force to the valve body, and a magnetic field adjusting means to adjust the solenoid magnetic field intensity applied to the valve body, and thereby adjusting the pressing force and magnetic field intensity individually. CONSTITUTION:This arrangement includes a solenoid 25, which performs opening/ closing operation by driving a needle valve 24 having a magnetic member 24b with the magnetic field generated by current supply control, and a spring 67 which is to apply pressing force to said needle valve 24. Further are furnished a pressing force adjusting means for spring pressing force and a magnetic field adjusting means to adjust the magnetic field intensity applied to the needle valve 24. Through adjustment of the pressing force of the spring to the needle valve 24, the pressure to the needle valve 24 can also be increased/decreased accordingly by increase/decrease of said pressing force to the needle valve 24. Adjustment of the magnetic field intensity to the needle valve 24 provides control of factors for the amount of movement such as motion acceleration etc. of the needle valve 24. Thus adjustments can be made separately and the injection amount can be adjusted independently according to the load range.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application J] The present invention relates to an overflow solenoid valve for determining a fuel injection amount used in a fuel injection pump, and further includes: A method of adjusting the amount of fuel injected from a fuel injection pump using the overflow solenoid valve is proposed.

[Prior art] In recent years, we have responded to exhaust gas regulations. Therefore, accurate and stable fuel injection amount and injection timing are required for diesel engines as well. In particular, EGR (exhaust gas recirculation system)
In order to reduce exhaust gas emissions in engines equipped with this type of fuel, more accurate and stable injection volume than before is required across the entire range of engine loads.

One of the reasons why the fuel injection amount for each fuel injection pump is inaccurate in response to the above command is due to variations in the operation of the overflow solenoid valves that determine the fuel injection amount of the fuel injection pumps. Conventionally, in order to achieve an accurate fuel injection amount, a technology has been developed to absorb the variation in response of each overflow solenoid valve by providing a delay time for the control signal.
JP-A-60-981/16).

Furthermore, not only the responsiveness of the overflow solenoid valve but also variations in the operation itself affect the injection amount. As a solution to this problem, a method has been proposed in which the load on the spring is adjusted using a screw R structure.

[Problems to be Solved by the Invention] However, in addition to the spring load that biases the valve body, factors that cause variations in the operation itself include: (1) fuel pressure applied to the valve body of the solenoid valve; (2) drive to the valve body. There is the suction force of the solenoid that provides the force.

Among these factors, ■The fuel pressure applied to the valve body of the solenoid valve is:
It becomes dominant in the high load range, and (2) the suction force of the solenoid that provides the driving force to the valve body becomes dominant in the low load range.

One of these factors, especially the fuel pressure, can be adjusted by adjusting only the spring load, but it is extremely difficult to solve both by adjusting only the spring load, that is, by applying only the biasing force to the valve body. Met.

SUMMARY OF THE INVENTION Therefore, the present invention employs the following configuration in order to solve the above problems.

[Means for Solving the Problems] That is, the first invention compresses fuel by the rotation of the engine, increases the pressure of the fuel, injects the fuel into the engine, and prevents overflow of the fuel. In overflow solenoid valves used in fuel injection pumps, which determine the amount of fuel injected by lowering the fuel pressure and ending the injection, the magnetic field generated by energization control causes the valve body containing a magnetic material to A solenoid that is driven to perform opening and closing movements; a spring that biases the valve body; a bias adjustment means that adjusts the biasing force of the spring; The gist of the invention is an overflow solenoid valve characterized by comprising: a magnetic field adjusting means for adjusting; It is used in fuel injection pumps that determine the amount of fuel to be injected by injecting it into the engine and lowering the fuel pressure due to fuel overflow and ending the injection.It is generated by energization control. A solenoid that uses a magnetic field to drive a valve body having a magnetic material to perform an opening/closing operation, a spring that biases the valve body, a bias adjustment means that adjusts the bias force of the spring, and a force generated in the solenoid. A method for adjusting the amount of fuel injection using an overflow solenoid valve, comprising: a magnetic field adjusting means for adjusting the strength of the magnetic field with respect to the valve body; and adjust the fuel injection amount using the magnetic field adjustment means so that the fuel injection amount becomes a predetermined injection amount scheduled for a low load or medium load state, and also adjust the driving state of the fuel f-1 injection pump. An injection amount adjustment method, characterized in that the engine is set in a high load state and the fuel injection amount is adjusted by the bias adjustment means so that it becomes a predetermined injection amount scheduled for the high load state. The summary is as follows.

[Operation] Fuel pressure can be controlled by adjusting the biasing force of the spring provided in the overflow electromagnetic valve of the first invention against the valve body by the biasing force i[E means. That is, as the force exerted on the valve element increases or decreases, the pressure of the fuel applied to the valve element also increases or decreases accordingly.

The attraction force of the solenoid can be controlled by adjusting the strength of the magnetic field applied to the valve body using the magnetic field adjusting means.

That is, it is possible to control movement factors such as the movement acceleration of the valve body.

The injection amount adjustment method of the second invention adjusts each adjustment means of the electromagnetic valve according to the load range so that the actual injection amount matches the fuel injection amount at a predetermined load of the fuel injection pump. do. That is, when the engine is in a low-load or medium-load state, the magnetic field adjustment means is used to adjust it, and when the engine is in a high-load state, the energization adjustment means is used to adjust it. In this way, a precise injection amount can be achieved over the entire load range.

Next, the present invention will be explained in detail.1. The present invention is limited to these.2. The present invention is not limited to the present invention, but includes various embodiments without departing from the gist thereof.

Embodiment] FIG. 1 shows a schematic configuration of a fuel injection pump 1 in which a solenoid valve according to an embodiment of the first invention is used.

The fuel injection pump 1 is an electromagnetic spill metering fuel injection pump based on a Bosch type distribution fuel injection pump. The fuel injection pump 1 is driven by a drive shaft 2.
A vane type feed pump 3 is rotated in conjunction with an engine (not shown).

The vane type feed pump 3 introduces fuel in a fuel tank (not shown) from an inlet 4 through a filter, pressurizes this fuel to the pressure set by a regulator valve 5, and then pumps the fuel. The fuel is supplied to a fuel chamber 6 formed within the injection pump 1.

The drive shaft 2 drives a plunger 8 via a coupling 7. This coupling 7 integrally rotates the plunger 8 in the rotational direction, but when the plunger 8 reciprocates in the axial direction, it freely allows this axial movement. It is integrated. The face cams are pressed against a cam roller 11 by a spring 10, and when the cam ridges of these face cams 9 ride on the cam roller 11 due to the contact between these face cams and the cam roller 11, the plunger 8 is reciprocated. The number of times (four times in this case) that corresponds to the number of cylinders of the engine (not shown) during one rotation of the 1-land gear 8
is reciprocated only.

The plunger 8 is slidably and precisely fitted into a head 12 attached to the fuel injection pump 1, and the head 12 and the end face of the plunger 8 form a cylinder 1 chamber 13. Suction grooves 14 are formed on the circumferential surface of the end of the plunger 8, and during the suction stroke of the plunger 8, that is, when moving to the left in FIG. When the fuel chamber 12 is connected to a suction bow 1 (not shown) provided in the pump chamber 12, fuel is sucked from the fuel chamber 6 into the pump chamber 13. Further, during the compression stroke of the plunger 8, that is, while moving to the right in FIG.
7, and is injected from B through the discharge valve 18 into the combustion chamber of the engine by an injection valve (not shown).

The above-mentioned bong 7 chamber 13 has a solenoid valve spill type fuel metering mechanism (
A solenoid valve) 20 is connected. That is, the pump chamber 13
are communicated with the fuel chamber 6 through overflow passages 21 and 22, and the overflow passage 21 is opened and closed by a solenoid valve 23. The solenoid valve 23 operates a needle valve 24 by a solenoid 25. When the solenoid 25 is energized, the needle valve 24 is lifted and the pump chamber 13 is opened to the overflow passage 2.
1.22 to the fuel chamber 6. Therefore, when the solenoid valve 23 is operated during the compression stroke of the plunger 8, the fuel pressurized in the pump chamber 13 flows into the overflow passage 21.2.
2 to the low pressure side fuel chamber 6, the fuel is no longer sent to the injection passage 17 side, and fuel injection is stopped. This controls the amount of fuel injection to be supplied to the engine. In addition, Moe 1! A part of the fuel that has overflowed into the l chamber 6 is returned to a fuel tank (not shown) via C.

The timing to start energizing the electromagnetic valve 23 is determined by an electronic control circuit 26 including a microcomputer or the like.

The aforementioned cam roller 11 is held by a roller ring 27. This roller ring 27 indicates the fuel injection timing m6tll.
Lateral (activated by timer >30. During fuel injection)
The V1 adjustment mechanism 30 includes a timer screw 31, and one end surface of the timer piston 31 has a fuel pressure in the fuel chamber 6 of 11? use The fuel pressure in the fuel chamber 6 changes according to -1/2 of the engine rotational speed, that is, the rotational speed of the feed pump 3. When the fuel pressure in the fuel chamber 6 acts on one end surface of the timer piston 31, the timer piston 31 resists the force of the spring 32 acting on the curved surface and moves to the first end.
Moved to the left of the diagram. Such a timer piston 31
The reciprocating motion is transmitted to the roller ring 27 via the pin 33. In FIG. 1, the timer piston 31 is shown in a position perpendicular to the actual pigeon coop, and the timer piston 31 is actually
The first axis is oriented in a direction perpendicular to the plane of the paper.

Therefore, the reciprocating movement of the timer piston 31 rotationally displaces the roller ring 27 about the drive shaft 2 . Therefore, the cam roller 11 and the face cam 9 are relatively displaced in the circumferential direction, so the timing at which the cam ridge of the face cam 9 rides on the cam roller 11 is shifted, and the phase of the reciprocating motion of the plunger 8 with respect to the drive shaft 2 changes. . As a result, the communication timing between the distribution boat 16 and the injection passage 17 changes, so the fuel injection timing is automatically adjusted.

The roller ring 27 includes, for example, an electromagnetic pickup type,
A timing detector 35 such as a Hall element type or an optical angle detection type is attached, and a pulser 36 is fixed to the drive shaft 2. When one of the protrusions 37 formed on the pulser 36 crosses the timing detector 35 due to the rotation of the drive shaft 2, the timing detector 35
generates a signal. This signal is transmitted to the electronic control unit 26.
sent to. When the electronic control device 20 receives the output signal from the timing detector 35, it uses this signal as a reference signal and after a predetermined period of time, outputs a power signal to the electromagnetic valve 23 to command its operation.

When the roller ring 27 is rotated by the operation of the timer 30, the timing adjuster 35 is also rotated by the same phase as the roller ring 27. Therefore, when the fuel injection timing is adjusted, the reference signal sent to the electronic control unit 26 also shifts by the same phase, so the operating timing of the solenoid valve 23 changes, and the overflow timing also changes by the difference in the reciprocating timing of the plunger 8. It is designed so that there is no change in the injection amount.

The electronic control circuit 26 uses various sensors to detect the operating state of the engine, such as an accelerator pedal sensor 41 that detects the position (depression jt) of the accelerator pedal 40, a rotation speed sensor (not shown) that detects the rotation angle of the engine, or In addition to the intake temperature sensor etc. being connected, the output of the timing detector 35 mentioned above is also connected, and the pulser 3
6, it is configured to detect a pulse signal corresponding to the rotational phase of the face cam 9 of the fuel injection pump 1 as described above. Further, the electronic control circuit 26 outputs a power signal to the fuel control mechanism 20 to energize the solenoid 25 of the connected electromagnetic valve 23 after a preset time or a time calculated from various conditions has elapsed. hand,
Open and close it.

Next, details of the fuel metering mechanism 20, which is an embodiment of the first invention, will be explained with reference to FIG.

A cylindrical spool seat member 53 is inscribed in the housing 51 made of a magnetic material, and a portion 53a of the spool seat 1 is formed at the tip of the spool seat member 53. A fuel passage hole 53b is opened in the center of the spool seat member 53a, and the spool seat member 5
A passage 53c passes through the cylindrical peripheral wall of No.3. The passage hole 53b and the passage 53c communicate with the overflow passage 21 or the overflow passage 22, respectively, so that the communication and cutoff between the two hot flow passages 21 and 22 are controlled by the fuel adjustment Wf.
It can be done in lI20. Note that the passage 54 and the passage 22a provided in the head 12 are for adjusting the pressure of the fuel in the housing 51, and are made to be the same as the pressure in the fuel chamber 6.

The spool sheet member 53 has a closure 4j 5 at one end.
A cylindrical spool 55 having a diameter of 5 a is slidably inscribed therein. The closed end 55a has a through hole 55b in the center.Normally, the spool 55 is biased toward the spool seat portion 53a by a spring 55c, so the closed end 55a comes into close contact with the spool seat portion 53a. However, the overflow passages 21 and 22 are closed. Inside the spool 55, the spool 55 is slidably provided with a cylindrical needle seam I.5 having a closed end 57a at one end.
7 is provided. The needle seat 57 is fixed to the housing 51. Furthermore, a round rod-shaped needle valve 24 is slidably inscribed in the needle seat 57. The needle valve 24 has a tapered tip 2
4a, and by coming into contact with the closed end 57a of the needle seat 57, the through hole 57b of the closed end 57a is closed.

A magnetic member 24b is fixed to the curved end of the needle valve 24,
The magnetic member 24b is arranged within a central space 25a of the solenoid 25 provided within the housing 51.

The end face 51a of the housing 51 is provided with a slide bin 63 made of a magnetic material that is screwed into the end face 51a, and the slide bin 63 can be rotated about its axis to allow movement into and out of the housing 51. .

Further, the slide bin 63 has a threaded hole 63a in the center. The threaded hole 63a has a screw-shaped adjustment pin 6.
5 are screwed together. By rotating the adjustment bin 65 about its axis, the adjustment bin 65 can be moved freely relative to the slide bin 63.

The stepped portion 57c of the needle sea 1-57 and the needle valve 9
．． A spring 67 is disposed between the locking protrusion 24c of No. 4 and urges the needle valve 24 in a direction to remove it from the needle seam 1-57. In addition, the above adjustment bin 65
A spring 69 is disposed between the needle valve 24 and the magnetic member 24b of the needle valve 24 to connect the needle valve 24 to the needle seam.
・It is biased in the direction of insertion into 57. Due to the balance of the spring 67 and the six springs, the needle valve 2
The pressure on the needle seat 57 of 4 is determined, and the fuel pressure on the needle valve 24 is also determined.

In this fuel metering mechanism 20, when a power signal is output from the electronic control circuit 26 to the solenoid 25, an attractive force is applied to the inside of the solenoid 25 against the magnetic member 24b, and the through hole 57b of the needle seat 57 is Open. As a result, the gap 7 between the spool 55 and the needle seat 57
The pressure in the gap 73 between the spool sheet 53 and the spool 55 decreases momentarily, and the pressure in the gap 73 between the spool sheet 53 and the spool 55 becomes weaker.
5 is separated from the spool sheet 53. Due to this,
The passage hole 53b and the passage 53c communicate with each other, and the hot flow passages 21 and 22 communicate with each other, thereby reducing the fuel pressure and stopping fuel injection.

When the slide bin 63 is inserted, the slide bin 63
Since the gap l between the magnetic member 24F and the magnetic member 24F becomes small, the influence of the initial magnetic force is large and the response speed becomes fast. on the other hand,
When the slide bin 63 is removed, the gap l becomes large, so the influence of the initial magnetic force is small and the response speed becomes slow. In this way, responsiveness can be adjusted.

When the adjustment bin 65 is inserted, the spring 69
The load on the needle valve 24 increases, and the fuel pressure applied to the needle valve 24 increases when the valve is opened. On the other hand, when the adjustment bin 65 is removed, the load on the spring 6 is reduced, and the fuel pressure applied to the needle valve 24 is lowered when the valve is opened. That is, for example,
When the fuel pressure generated by the pump chamber 13 is low, the needle valve 24 opens early; on the other hand, when the fuel pressure is low, the needle valve 24 opens quickly.
4 opens the valve with a delay. Therefore, adjust bin 65
By adjusting the load, the valve opening timing and valve opening transient response can be adjusted in accordance with the fuel pressure generated from the pump chamber 13 of each fuel injection pump.

Next, the injection amount adjusting method which is an embodiment of the second invention will be explained in the third embodiment.
This will be explained with reference to the figures. FIG. 3 is a flowchart showing the working process for adjusting the injection amount.

First, attach the fuel injection pump l to be adjusted to a measuring device that can set the conditions for various diesel engines. Such measuring devices are already known for regulating fuel injection pumps of diesel engines.

Next, as shown in the flowchart of FIG. 3, in step 100, the rotation of the drive shaft 2 of the fuel injection pump 1 and the injection timing by the fuel injection timing regulator 'M (timer) 30 are set to a low or medium load value. do.

Next, in step 110, the amount of fuel injected from the injection valve (not shown) via the discharge valve 18 is measured.Next, in step 120, it is inspected whether the measured amount of the injection lid is an appropriate amount. That is, it is checked whether or not the fuel injection amount matches a target fuel injection amount that is preset according to the load condition (for example, the output value of the accelerator pedal sensor 41 and the engine rotation speed in 13i1). If they do not match here, the insertion amount of the slide bin 63 is adjusted by rotating the slide bin 63 in step 130. By this adjustment, the distance between the magnetic member 24b of the needle valve 24 and the slide bin 63 forming part of the magnetic circuit changes, and the influence of magnetism changes.Next, the injection amount is measured again in step 110. and is checked in step 120. If they do not match, the slide bin 63 is adjusted again in step 130.
This is repeated, and if it is determined that they match in step 120, the solenoid 2 that affects the injection amount at low or medium load
5 suction force will be accurately adjusted.

Next, in step 140, the rotation of the drive shaft 2 and the injection timing are set to high load values.Next, in step 150, the withdrawal of fuel injected from the injection valve is measured.Next, in step 160 Then, it is checked whether the fuel injection amount matches a target fuel injection amount that is preset according to the load state. If it doesn't match here,
In step 170, the slide bin 63 is fixed and the adjustment bin 6 is adjusted by rotating only the adjustment bin 65.
Adjust the insertion amount in step 5. With this adjustment, the needle valve 2
Next, the injection amount is measured again in step 150 and inspected in step 160. If they do not match, go to step 170 again and adjust the adjustment bin 6.
5 is repeated, and if it is determined in step 160 that they match, only the fuel pressure applied to the needle valve 24, which affects the injection amount under high load, will be accurately adjusted.

Adjustment between the high load area and the low or medium load area may be performed in the reverse order.

In this way, the fuel injection amount in the received load region and the injection amount in the low or medium load region can be adjusted independently of each other.

Therefore, it is possible to realize an engine that can precisely control the fuel injection amount in the entire negative back region, and prevent black smoke generation and insufficient output under a wide range of operating conditions.

Also, when assembling the fuel F-4 injection pump 1, you can assemble the fuel injection pump 1t without making any special precise adjustments! - After assembly to the engine, precise adjustment that absorbs the largest amount of errors can be easily carried out by simply rotating the slide bin 63 and adjustment bin 65, taking into consideration engine machine differences and other influences. can.

The first invention provides an overflow solenoid valve used in a fuel injection pump, including a biasing adjustment means for adjusting the biasing force of a spring biasing the valve body, and a magnetic field generated in the solenoid. χ・t
By providing a magnetic field adjusting means for adjusting the strength of the magnetic field, the urging force of the spring and the strength of the magnetic field can be adjusted separately, and the fuel injection amount can be adjusted independently according to the load range.

A second aspect of the present invention is to set the driving state of the fuel injection pump to a low load or medium load state of the engine so that the fuel injection amount becomes a predetermined injection amount scheduled for the low load or medium load state. Adjustment is made by the magnetic field adjustment means, and the driving state of the fuel injection pump is set to a high load state of the engine, so that the fuel discharge amount becomes a predetermined discharge amount scheduled for the high load state. Since the fuel injection amount is adjusted using a power adjustment means, the fuel injection amount can be precisely adjusted in the entire load range according to the operating conditions.

Preventing black smoke and preventing insufficient output can be solved simultaneously and easily.

[Brief explanation of drawings]

FIG. 1 is a schematic structural explanatory diagram of a fuel injection pump in which a solenoid valve according to an embodiment of the first invention is used, FIG. 2 is an end view of the solenoid valve according to the embodiment, and FIG. 1 is a flowchart showing the steps of an embodiment of the invention. 1...Fuel injection pump 20...Fuel metering mechanism 21...Overflow passage 22...Overflow passage 23... ... Solenoid valve 24 ... Needle valve 24b ... Magnetic member 25 ... Solenoid 26 ... Electronic control circuit 111 ... Accelerator Pedal sensor 53...Spool seat member 53a...Spool seat 1 section 55...Spool 57...Needle seat 63...Slide bin 63a... ...Threaded hole 65 ... Adjustment bin 67 ... Spring 69 ... Spring

Claims (1)

[Claims] 1 Engine rotation compresses fuel, increases the pressure of the fuel, and injects the fuel into the engine, and also reduces the pressure of the fuel due to overflow of the fuel and injects the fuel. In the overflow solenoid valve used in the fuel injection pump that determines the amount of fuel to be injected, the magnetic field generated by the energization control drives the valve body with a magnetic material to open and close the solenoid. , a spring that biases the valve body; a bias adjustment device that adjusts the biasing force of the spring; and a magnetic field adjustment device that adjusts the strength of the magnetic field generated in the solenoid with respect to the valve body. Features a solenoid valve for overflow. 2. The overflow solenoid valve according to claim 1, wherein the biasing adjustment means comprises a mechanism that adjusts the amount of compression of the spring by the amount of rotation of the screw. 3. The overflow electromagnetic valve according to claim 1 or 2, wherein the magnetic field adjusting means comprises a mechanism for adjusting the distance between a part of the magnetic circuit and the magnetic body of the valve body by the amount of rotation of a screw. 4 Compressing the fuel by the rotation of the engine, increasing the pressure of the fuel, injecting the fuel into the engine, and reducing the pressure of the fuel due to the overflow of the fuel and ending the injection, A solenoid used in a fuel injection pump that determines the amount of fuel to be injected, which uses a magnetic field generated by energization control to drive a valve body containing a magnetic material to open and close the valve body, and a spring that acts on the valve body. A method for adjusting a fuel injection amount using an overflow solenoid valve, comprising: a biasing adjustment means for adjusting the biasing force of the spring; and a magnetic field regulating means for regulating the strength of a magnetic field generated in the solenoid with respect to the valve body. The drive state of the fuel injection pump is set to a low load or medium load state of the engine so that the fuel injection amount becomes a predetermined injection amount scheduled for the low load or medium load state, Adjusted by the magnetic field adjusting means, and setting the driving state of the fuel injection pump to a high load state of the engine so that the fuel injection amount becomes a predetermined injection amount scheduled for the high load state, A method for adjusting an injection amount, characterized in that adjustment is performed using the bias adjustment means.