JPS6036770A - Fuel injection control device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To permit to adjust injection timing easily without stopping the engine once, improve the reliability of the device and reduce the cost of the device by a method wherein a pressure port and a drain port are communicated temporarily to permit to shorten the stroke of a spool. CONSTITUTION:When the internal-combustion engine is revolved and the injection timing comes, a left side solenoid 109 is demagnetized and the right side solenoid 108 is excited. The spool 105 is energized left-wardly by the force of the solenoid 108 and an outlet port 62 is communicated with the pressure port 63. Pressure oil is supplied from the pressure port 63 to the servo pressure chamber of a fuel valve through the outlet port 62, therefore, a servo piston descends and the fuel injection may be effected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fuel injection system for an internal combustion engine that allows easy adjustment of fuel injection timing, fuel injection amount, and fuel injection pressure without stopping the internal combustion engine and without depending on the rotational speed of the internal combustion engine. This invention relates to an injection control device.

In general, in internal combustion engines, particularly diesel engines, fuel injection timing has a large effect on internal combustion engine performance, particularly fuel consumption rate. In addition, the fuel consumption rate can be reduced by increasing the fuel injection pressure and shortening the injection period to increase combustion efficiency, but high-pressure injection when the internal combustion engine is under low load may cause diesel knock. This results in a shortened lifespan of the internal combustion engine and excessive noise.

The optimal values for injection timing and pressure vary greatly depending on the operating conditions of the internal combustion engine and the quality of the fuel oil, so if the fuel injection timing and fuel injection pressure could be freely adjusted even while the internal combustion engine is running, it would be possible to significantly reduce the amount of fuel used. Savings can be made without forcing the internal combustion engine to overwork, and considering the current situation where oil prices are soaring, it will generate large profits.

Conventionally, a fuel injection device for an internal combustion engine is configured by directly connecting a fixed stroke fuel injection pump that is driven in synchronization with the operation of the internal combustion engine and an automatic injection nozzle with a shutoff valve via a fuel injection pipe. Widely adopted around the world. In this conventional fuel injection system, the fuel injection timing is determined by the cam setting position, and when changing the fuel injection timing, it is necessary to change the setting position of the cam on the camshaft, and the internal combustion engine must be temporarily stopped. I had to.

In order to solve this problem, the applicant has already applied for patent applications No. 57-42391 and No. 57-46.
According to the fuel injection device in No. 619, a fuel control valve driven by a cam with an advance device is provided between a fixed stroke fuel injection pump and an automatic injection nozzle with a shutoff valve, and a fuel control valve driven by a cam with an advance device is provided between the fixed stroke fuel injection pump and the shutoff valve. By using the cam with an advance device to change the connection timing of the passage between the automatic injection nozzle and the automatic injection nozzle, the fuel injection timing can be adjusted without stopping the internal combustion engine. However, in such a device, the fuel injection pressure is determined by the rotational speed of the internal combustion engine and the dimensions of the injection nozzle, and cannot be freely adjusted.

On the other hand, in a fuel injection device already known in JP-A-56-143344, an injection nozzle with a shutoff valve is equipped with an electro-hydraulic servo valve, and the fuel flow path is switched using liquid pressure other than the fuel. Alternatively, fuel stored in a high-pressure fuel source is injected into the cylinder from an injection nozzle, and the start and end of the injection is controlled by an electric pulse signal applied to the electrohydraulic servo valve. According to such a device,
The fuel injection timing and fuel injection amount are determined by the sending timing and pulse width of the electric pulse signal, and the fuel injection pressure is determined by the fuel pressure accumulated in the high-pressure fuel source. The quantity and fuel injection pressure can be freely adjusted independent of the internal combustion engine speed and cam installation. However, such devices require an expensive electro-hydraulic servo valve as well as a hydraulic power source to operate the valve, which increases the initial cost, and furthermore, electro-hydraulic servo valves are generally susceptible to contamination due to impurities in the oil. Because it is weak to
There is a problem in that it is necessary to control the dirt of the hydraulic oil and the operating cost increases.

Furthermore, when attempting to achieve high fuel injection pressure in the above three types of fuel injection devices, the strength of the components and connections on which the fuel injection pressure acts, such as the fuel injection pump, fuel injection pipe, and fuel injection valve, must be Therefore, the equipment becomes expensive.

An object of the present invention is to solve the above-mentioned technical problems, and to easily adjust the fuel injection timing, injection amount, and fuel injection pressure while the internal combustion engine is in operation, without having to temporarily stop the engine. It is an object of the present invention to provide a fuel injection control device for an internal combustion engine that is capable of improving reliability and reducing cost.

The present invention will be explained in detail below with reference to one drawing. FIG. 1 is a block diagram showing an embodiment of the present invention. ii The pressure source 1 is connected to the fuel valve 3 via the solenoid valve 7 by a refueling conduit 38, and the second pressure source 2 is also connected to the fuel valve 3 via the solenoid valve 4 by a control conduit 49. Solenoid valve 4゜7
is controlled by an electrical signal from a control circuit 8. Each component will be explained in turn.

FIG. 2 is a sectional view showing one embodiment of the fuel valve 3 according to the present invention. The fuel valve 3 is composed of a first part, a supply part 2, and a third part, which are screwed together to form one fuel valve 3. That is, the first part is the lid 10, which is attached to the second part by bolts 14. Control hole 15 bored in the center of the lid 10
is connected to the solenoid valve 4 via a control conduit 49.

Inside this control hole 15, a throttle member 19 and a check valve 20 are disposed, and the hydraulic oil is configured to freely flow into the fuel valve 3 from the control conduit 49, but to be throttled when flowing out. has been done.

The second part is a pump 11 driven by hydraulic pressure introduced through the control hole 15.

The pump 11 has a servo piston 17, a pump piston 18, and a check valve 46 inside a casing 16. The pump piston 18 is guided in the axial direction within the casing 16 together with the servo piston 17, which has an outer diameter larger than that of the servo piston 18, and is guided in the axial direction within the casing 16.
7 and the pump piston 18 are connected so as to interact with each other. Therefore, the hydraulic pressure introduced into the servo pressure chamber 21 which is restricted by the upper surface of the servo piston 17 and the lid 10 is doubled by the cross-sectional area ratio of the servo piston 17 and the pump piston 18, and the pressure is increased by the lower surface of the pump piston 18. It acts on the pump chamber 33 which is restricted.

Note that the cross-sectional area of the flow path of the throttle member 19 installed inside the lid 10 is sufficiently smaller than that of the control hole 15 and the control conduit 49, so that the speed of oil discharge from the servo pressure chamber 21 is lower than that of the throttle member 19.
It is now possible to specify The time tM required for draining the oil must be selected to be sufficiently longer than the time tE required for injection, but so that tM+tE is smaller than the time 12 required for one cycle of the internal combustion engine. Since the amount of fuel filling the pump chamber 33, that is, the amount of fuel to be injected, is adjusted by adjusting the operating time of the electromagnetic valve 7, increasing the tMO value helps improve control accuracy.

The third part is a well-known automatic injection nozzle 12 with a closing valve, in which a spring casing 22, a needle casing 23 and a nozzle 24 are enclosed in a cap nut 25.
It is screwed and attached to the lower part of the pump 11, that is, the casing 16. A closing needle 27 is guided in the needle casing 23 , and a spring chamber 28 in the spring casing 22 is located in the upper part 27 a of the closing needle 27 .
A spring receptacle 29 is fitted inside. A spring 31 is installed between the spring receiver 30, which is located at the upper part of the spring chamber 28 and limits the opening stroke of the closing needle 27, and the spring receiver 29, and biases the closing needle 27 in the closing direction. . A fuel reservoir 26 and a nozzle 24 are arranged in the lower part 27b of the closing needle 27, and cooperate with the closing needle 27 to form a closing valve. The fuel reservoir 26 communicates with the pump chamber 33 of the pump 11 via passages 36a, 36b formed in the spring casing 22 and the needle casing 23.

Inside the casing 16 of the pump 11, there are oil supply holes 34a,
34b is formed, the blade end of which is connected to the supply hole 35 provided in the lid 10, and the other end is connected to the pump chamber 33 via a recess 37 provided in the upper surface of the spring casing 22. ing. A check valve 46 is provided in the fuel supply hole 34 to prevent the fuel from flowing back into the fuel supply pipe 38 when the fuel is injected from the automatic injection nozzle 12, and to prevent the fuel from flowing back into the fuel supply pipe 38. can be filled into the pump chamber 33.

A passage 39 opening into the pump chamber 33 is formed inside the pump piston 18 and communicates with an annular passage 40 formed on the upper side surface of the pump piston 18 . These passages 39, 40 serve effectively to drain the fuel in the pump chamber 33 to the supply side near the end of the downward stroke of the pump piston 18, thereby improving the so-called "run-off" of the fuel. That is, one end of the horizontal hole 41 formed in the casing 16 is connected to the backflow prevention valve 46 in the oil supply hole 34.
The fuel leaking into the spring chamber 28 along the annular passage 40 is opened on the upstream side, and the other end can communicate with the annular passage 40. The oil flows out from the drain oil conduit 44 to the tank 86 (see FIG. 1) outside the fuel valve 3 through the drain oil hole 43 located in the drain hole 43 .

1--Fuel leaking along the boviston 17 and the pump piston 18 is collected in an annular gap 45 formed slightly above the lower end of the vertical hole 32 into which the servo piston 17 is fitted. This annular gap 45 opens into the oil drain passage 42 .

As another embodiment, a check valve (not shown) may be provided in the middle of the oil drain path 42. This check valve prevents the fuel, once drained into the oil drain pipe 44, from entering the annular gap 45 or the spring chamber 28.
This prevents leaked fuel from interfering with the downward movement of the servo piston 17.

Note that the pump piston 18 descends and the spring casing 2
Since the annular gap 45 is located slightly above the lower limit position of the servo piston 17, the fuel sealed between the lower surface 32a of the vertical hole 320 and the inner surface of the servo piston 17 is compressed at the lower limit position, thereby relieving the impact of the servo piston 17 and pump piston 18 at the lower limit position.

The maximum amount of fuel introduced into the pump chamber 33, that is, the maximum injection -1EV, is limited by the height of the protrusion 48 of the lid 10, so by changing this height, it can be adjusted for various internal combustion engines. The maximum injection amount can be regulated.

As another structure for regulating the maximum injection amount, an intermediate piece 47 may be provided between the servo piston 17 and the pump piston 18, and the length of this intermediate piece 47 may be selected.

Referring again to FIG. 1, the description of the components other than the fuel valve 3 will be continued. The first pressure source 1 is connected to the supply hole 35 of the fuel valve 3 via a fuel conduit 50, a solenoid valve 7 and a fuel supply conduit 38. The first pressure source 1 includes a fuel tank 51, a fuel pump 52 that increases the pressure of the fuel from the fuel tank 51, and sends the fuel to the fuel conduit 50, and a pressure regulating valve for keeping the fuel pressure in the fuel conduit 50 constant. 53 are provided. In order to prevent pressure pulsations within the fuel conduit 50, an accumulator 54 may be provided in the middle of the fuel conduit. The electromagnetic valve 7 that controls the connection of the flow path between the fuel conduit 50 and the oil supply conduit 38 is driven by an electric signal from the control circuit 8. That is, the driving time of the electromagnetic valve 7 becomes the metering time tM, during which time the fuel valve 3 is filled with fuel. Since the filling speed is also affected by the viscosity of the fuel, in order to improve the control accuracy of 1i11it, the first pressure source 1 is equipped with a temperature control device (
(not shown) may be provided.

The second pressure source 2 is connected to the fuel valve 30 control hole 15 via a pressure conduit 55, a solenoid valve 4 and a control conduit 49. The second pressure source 2 includes a tank 58 and a boost pump 5 that boosts the pressure of the fuel from the tank 58 and sends the fuel to the pressure conduit 55.
9 and a pressure regulating valve 60 for regulating the pressure within the pressure conduit 55. The accumulator 61 is connected to the pressure conduit 5 to prevent pressure pulsations in the pressure conduit 55.
It may be provided in the middle of 5. The tank 58 is the fuel tank 5
1 can be omitted by sharing the pressure source 1 with the first pressure source 1 and the second pressure source 2.

The solenoid valve 4 has an outlet boat 62, a pressure port 3, and a drain boat 64, and the control conduit 49 is connected to the outlet boat 62.
, the pressure conduit 55 is connected to the pressure port 3, and the return conduit 76 is connected to the drain boat 64. The other end of the return conduit 76 is connected to the tank 58.

The solenoid valve 4 connects the outlet boat 62 to either the pressure port 3 or the drain boat 64 in response to an electrical signal sent from the control circuit 8 . 1, that is, it is possible to select whether the control conduit 49 is connected to the pressure conduit 55 or to the return conduit 76. The control circuit 8 includes an angle detector (
An electrical signal sent from a device (not shown) is input.

When the rotation angle of the internal combustion engine reaches a preset value (injection timing), the control circuit 8 drives the solenoid valve 4 and switches the control conduit 49 from the return conduit 76 to the pressure conduit 55.

In the case of an internal combustion engine having multiple cylinders, a solenoid valve and a fuel valve are connected to the branch pipes 50B+50b, 506 of the fuel conduit 50, and the branch pipe 55& of the pressure conduit 55.

Control valves 55b and 55c can be connected to each other in the same manner as shown in FIG.

The first pressure source 1 has a pressure sufficient to push up at least the servo piston 17 and the pump piston 18 against the frictional force, taking into consideration the pressure loss in the throttle member 19 in the fuel valve 3 during oil drainage. Requires pressure. It is also conceivable to control the set pressure of the pressure regulating valve 53 in response to the rotation speed and/or load of the internal combustion engine. To change the set pressure, use a well-known positioner (not shown) to set the spring of the pressure regulating valve 53, or provide a diagonal notch in the valve body of the pressure regulating valve 53 and rotate the valve body. Accordingly, the valve stroke at which the oil drain hole formed in the valve seat communicates with the notch may be changed.

The pressure of the second pressure source 2 defines the fuel injection pressure. For example, if the ratio immediately after the servo piston 17 and the pump piston 1B is 2.5:1, the pressure of the second pressure source 2 is set to 200 atmospheres. If selected, 200 x 2.5:1,
High pressure injection of 250 atmospheres can be achieved. It is also conceivable to control the set pressure of the pressure regulating valve 60 in response to the rotation speed and/or load of the internal combustion engine. This works effectively to prevent diesel knock by lowering the injection pressure and therefore the fuel injection rate when the internal combustion engine is in a cold state. To change the set pressure, use a well-known positioner (not shown) to adjust the setting position of the spring of the pressure regulating valve 60, or provide a diagonal notch in the valve body of the pressure regulating valve 60 and rotate the valve body. Accordingly, it is also possible to change the configuration in which the oil drain hole formed in the valve seat and the notch communicate with each other.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be explained. In the state shown in FIG. 1, the solenoid valve 4 is not energized and the outlet boat 62 and drain boat 64 are connected. That is, since the control conduit 49 is connected to the return conduit 76, the servo pressure chamber 21 of the fuel valve 8 is open to the pressure of the tank 58 (atmospheric pressure) and remains in the state shown in FIG. The pump chamber 33 is filled with fuel. When the rotation angle of the internal combustion engine reaches a preset value (injection timing), the control circuit 8 drives the solenoid valve 1 in response to an output from an angle detector (not shown). This causes the outlet boat 62 of the solenoid valve 4 to be switched from the drain port 64 to the pressure port 3, i.e. the control conduit 49 pressure conduit 5
Connected to 5. Therefore, the hydraulic oil (fuel) flowing from the boost pumps 5 and 9 of the second pressure source 2 to the pressure conduit 55 is as follows:
It flows via the solenoid valve 4 into the control conduit 49 .

Referring to Fig. 2, the hydraulic oil flowing into the control conduit 49 flows into the fuel valve 30 control hole 15, flows into the servo pressure chamber 21 via the check valve 20, and urges the servo piston 17 downward. Therefore, the pump piston 18, which is arranged to interact with the servo piston 17, is also urged downward, and the pump! Since the fuel filled in the pump chamber 33 is compressed, the pressure of the fuel in the pump chamber 33 is increased.

Since the outer diameter of the servo piston 17 is larger than the outer diameter of the pump piston 18, the servo pressure chamber 2 is
1 is doubled and acts on the pump chamber 33. The fuel pressurized in the pump chamber 33 does not flow back into the fuel supply hole 34 because the check valve 46 is interposed, but instead flows through the passages 36a and 36b.
The fuel flows through the fuel reservoir 26 of the automatic injection nozzle 12 with a well-known shut-off valve, and is injected from the nozzle 24 into a cylinder (not shown).

When the pump piston 18 descends due to fuel injection and reaches its lower limit position, the annular passage 40 formed on the side surface of the pump piston 18 and the horizontal hole 41 communicate with each other. The fuel in the pump chamber 33 flows from the passage 39 in the pump piston 1B to the side hole 4.
1 to the oil supply hole 34. Then, the pressure of the fuel in the pump chamber 33 drops rapidly, so the fuel that was injected into the cylinder (not shown) from the automatic injection nozzle 12 with the closing valve sealed is shut off by the closing needle 27 biased by the spring 31. and the injection ends. At least the solenoid valve 4 is energized until the fuel injection ends, and the energization time is somewhat longer than the maximum injection time.

In the case of a large 4-stroke internal combustion engine, the crank angle is, for example, about 45 degrees.

After the fuel injection is completed, the electric signal from the control circuit 8 is cut off, the solenoid valve 4 is demagnetized, and the outlet boat 62 and the drain boat 64 are brought into communication again. The hydraulic oil in the servo pressure chamber 21 in the fuel valve 3 therefore flows via the control conduit 49 and the return conduit 76 to the tank 58 and flows into the servo pressure chamber 21.
1 is atmospheric pressure. Note that the fuel injection timing is determined by the control circuit 8.
It can be easily changed using the adjuster provided in the. If the optimal fuel injection timing is calculated according to the operating state of the internal combustion engine (for example, the rotational speed and torque), the effort of operating the regulator can be saved.

Next, when the electromagnetic valve 7 is energized by an electric signal sent from the control circuit 8, the fuel in the first pressure source 1 is transferred to the fuel conduit 5.
0 through the solenoid valve 7 to the fuel supply conduit 38, and the fuel valve 3
supplied to Referring again to FIG. 2, fuel flowing from the fuel supply conduit 38 to the supply hole 35 flows into the pump chamber 33 via the check valve 46. Some of the fuel is
Bypassing the horizontal hole 41, the annular passage 40 and the passage 3
9 into the pump chamber 33 until the horizontal hole 41 is blocked by the side surface of the pump piston 18 ◇ The fuel flowing into the pump chamber 33 urges the pump piston 18 upward, causing the pump piston 18 and its The servo piston 17 connected to the servo piston 17 is pushed up against the frictional force. As the servo piston 17 rises, the servo pressure chamber 2
The hydraulic oil displaced in 1 flows out of the control hole 15 into the control conduit 49 via the throttle member 19 and, since the solenoid valve 4 is in the first illustrated state, flows through the return conduit 76 into the tank 58. Although fuel also flows through the automatic injection nozzle 12 that communicates with the force pump chamber 38, the pressure of the first pressure source 1 (approximately 20 atmospheres) is lower than the opening pressure of the automatic injection nozzle 12 (for example, 20 atmospheres).
00 atm), no injection occurs.

When the electric signal from the control circuit 8 is cut off and the solenoid valve 7 is demagnetized, the fuel flowing from the first pressure source 1 to the fuel valve 3 via the fuel conduit 50 and the fuel supply conduit 38 is cut off, and the pump piston 18 The upward stroke (Ill amount stroke) stops and the state returns to the state shown in the first diagram. While the electromagnetic valve 7 is energized in this way, the fuel filled in the pump chamber 33 becomes the amount of fuel to be injected in the next vehicle. The maximum injection amount is determined by the length of the intermediate piece 47 and the height of the protrusion s48, so the maximum injection amount can be regulated according to the scale of the internal combustion engine, and even if the solenoid valve 7 breaks down, the injection amount will not be large enough to destroy the internal combustion engine. No torque is generated. It is assumed that the electric signal for exciting the solenoid valve 7 is sent out while the aforementioned solenoid valve 4 is demagnetized. The rotational speed of the engine can be controlled by controlling the control circuit 8 to interpret signals sent from a rotational speed detector (not shown) and adjusting the excitation time of the solenoid valve 7.

The throttle member 19 functions to regulate the filling speed of fuel into the pump chamber 33, and is useful for controlling the amount of fuel filling and improving the accuracy of metering. That is, if metering is performed slowly using the restricting member 19, precise metering becomes possible, so that the electromagnetic valve 7 does not need to have a high response (for example, 1 m5).

For example, at 1000 rpm, the injection period is crank angle 3.
In the case of a 4-cycle internal combustion engine at 5 degrees Celsius, the injection time tE is tH = 35/6 If control is desired, the response time of the solenoid valve must be at least 0.5 ms, so the only method available is to use an electrohydraulic servo valve.

However, according to the metering structure according to the present invention, the metering time tM only needs to be completed within one cycle.
A response of about ms is sufficient, and an electro-hydraulic servo valve is no longer required. Therefore, metering can be performed using an electromagnetic valve that is resistant to dirt and is inexpensive.

In order to regulate the filling speed of fuel into the pump w133, the structure in which a throttling member is provided on the oil drain side of the pump 11 as in the present invention is compared to the structure in which a throttling member is provided on the inflow side. It is excellent in the following aspects. That is, in the latter structure, the throttle member 19 is provided in the control hole 15 and inside the fuel supply hole 34, but with this structure, the amount of fuel is easily affected by disturbances, and there is a limit to the improvement of control accuracy. There is.

This will be explained below with reference to FIG. The relationship between various quantities related to the pump 11 can be expressed by the following group of equations.

pl-A1+(A2-AI)Pm-P2-A2+F'
---(11△r'l ”PO-Pt = 1 ・J
・-(21△P2 = P2 = K2-Qo ---
(31 Here, A1: Fr?1l of pump piston 18
iA2. Cross-sectional area of the servo piston 17 PQi Pressure of the first pressure source 1 (constant) pl, Pressure of the pump chamber 33 P21 Pressure of the servo pressure chamber 21 Pm; Pressure of the oil drain path 42 F; Frictional force of pump operation Ql; Filling flow rate Q2: Drainage oil flow rate, + inflow/side flow path resistance 2: Drainage side flow path resistance However, the tank pressure is assumed to be 0, and the pressure of the first pressure source 1 is assumed to be constant. Now, assuming that the flow path resistance on the inflow side and oil discharge side is constant (Kl, 2 = constant), the filling speed Q1 into the pump chamber 33 is determined by the differential pressure △P1, but if p□ is adjusted to be constant. Therefore, it is controlled by Pl (second equation). Furthermore, even if the speed QO of draining oil from the fuel valve 3 is specified, the filling speed Q
Since i is determined (4th equation), Qi is similarly defined by P2 (3rd equation). Therefore, if Pl or P2 is kept constant, the filling speed can be regulated to a constant value, but since the frictional force F accompanying the pump operation and fluctuations in the pressure Pm in the oil drain passage 42 act as disturbances, Pl and P2 are Fluctuations, 1
Even if the operating time tM of the solenoid valve 7 is specified, the filling amount will change. In order to reduce the influence of such disturbances, Fi
It is better to increase pl and p2. That is, by transforming the first equation, P2-A2+ (F-(A2-Al)Pm)=Pl-A
l --- In (1a), P2 ・A2 >> F − (A2-A1 ) Pm ”・
(51, the influence of disturbance (second term on the left side of equation 1) can be ignored. Without changing the dimensions of the fuel valve 3, Pi, p2
There are two ways to increase p□ or to increase 2, but increasing p□ increases the filling speed Q1, which is disadvantageous in that the metering time tM becomes shorter. will occur. This means that the metering time tM
This is because the longer the length, the more accurate the metering can be. In order to reduce the influence of disturbance without shortening the metering time tM, it is sufficient to increase 2. Furthermore, if 1 is made smaller, Pl also becomes larger. As described above, eliminating the throttle member on the inflow side and arranging the throttle member on the oil drain side is more effective in improving metering control accuracy.

The fuel injection pressure in this embodiment is determined by the pressure of the hydraulic oil in the servo pressure chamber 21, so by adjusting the pressure of the second pressure source 2, self-twisting can be achieved like a conventional injection device. It is possible to freely select the injection pressure without depending on the engine speed. This improves the economy and operability of the internal combustion engine. Further, the pressure of the hydraulic oil of the second pressure source 2 is controlled by the servo piston 17 inside the fuel valve 3.
Since the fuel is injected with the pressure doubled by the cross-sectional area ratio of the pump piston 18 and the
atmospheric pressure) can be easily and inexpensively realized. That is, the second
Including the pressure source 2 and the solenoid valve 4, the pressure conduit 55 and the control conduit 4
The withstand pressure of 9 may be small (for example, 350 atm), and no special development is required for sealing methods or pipe joints for each part, and conventional techniques can be used up to that point. In fact, an injection device that is constructed by connecting a fixed stroke fuel injection pump and an automatic injection nozzle with a shutoff valve directly via an injection pipe, which has been widely adopted in the past, requires a pressure resistance of 1000 atmospheres or more. There is.

FIG. 4 is a block diagram showing another embodiment of the present invention, and parts corresponding to those in the previous embodiment are given the same reference numerals. This embodiment differs from the previous embodiment in that a flow meter 87 is disposed in the middle of the fuel conduit 50. In the embodiment described above, the filling speed is regulated by the throttle member 19, but the speed is influenced by the temperature of the fuel and the pressure of the first pressure source 1, and the pulse width of the electric signal from the control circuit 8 is the same. However, there is a difference in the amount of fuel to be filled, KM, 1,000. flow meter 87
The signal from the flow meter 87 is applied to the control circuit 8, and by limiting the maximum pulse width of the electrical signal sent from the control circuit 8 in response to the signal from the flowmeter 87, an unexpected or undesirably large amount of It becomes possible to prevent fuel from being injected into the cylinder.

That is, the flow meter 87 works together with the control circuit 8 to realize the torque limit of the internal combustion engine and prevent overloading. It is also possible to perform further density correction by connecting the control circuit 8 to the control circuit 8.

FIG. 45 is a sectional view showing another embodiment of the fuel valve 3 according to the present invention. The shape of the throttle member is different from the embodiment shown in the second figure; in this embodiment, the throttle member 88 is formed by a thin-bladed orifice. The diaphragm member 19 of the above-mentioned embodiment
Although the fuel oil is excellent in terms of life and strength, it has the disadvantage that the viscosity changes when the temperature of the fuel oil changes, so the filling rate changes. According to the thin-blade orifice adopted in this example, although the strength is inferior, the filling rate does not change depending on the temperature of the fuel oil.

FIG. 6 is a sectional view showing still another embodiment of the fuel valve 3 according to the present invention. What is noteworthy about this example is that
A position detector 89 is provided inside the thing 16. As described above, since the filling speed is affected by the temperature of the fuel and the pressure of the first pressure source 1, there is a limit to the control accuracy of the injection amount in the embodiment shown in the second figure. According to this embodiment, the signal from the position detector 89 is applied to the control circuit 8. By controlling the pulse width of the electric signal according to the signal from the position detector 89, the temperature of the fuel and the first pressure source 1 can be controlled.
It becomes possible to precisely adjust the injection amount to a desired value without depending on the pressure.

As another embodiment of the present invention, the pump 11 and the injection nozzle 1
Pump 2 has an integral structure, but due to placement and maintenance considerations, pump 1
1 and the injection nozzle 12 may be separated and connected by an injection pipe.

FIG. 7 is a configuration diagram showing still another embodiment of the present invention. In the embodiment described above, the throttle member 19 was built into the fuel valve 3, but the throttle member 90 may be disposed in the middle of the return conduit 76 as in this embodiment. Note that in the fuel valve 3, the throttle member 19 and the check valve 20 are no longer necessary.

FIG. 8 is a configuration diagram showing still another embodiment of the present invention. In the above embodiment, two solenoid valves 4°7 were used.
Control is possible even with one solenoid valve 91 as in this embodiment. The control operation of the solenoid valve 910 is performed in response to an electrical signal from the control circuit 8, and is performed through the control conduit 49, the pressure conduit 55, the return conduit 76, the refueling conduit 38, and the fuel conduit 5.
Convert the connection state of 0. In this embodiment, there is one solenoid valve.
In internal combustion engines, fuel injection timing is an important factor that affects fuel combustion performance, and the position of the piston in the combustion chamber also Correspondingly, it is set by the crank angle, so the higher the engine speed, the shorter the time it takes to adjust the crank angle by one degree. Therefore, in order to precisely control the combustion injection timing in the present invention, it is essential to improve the operating speed of the solenoid valve 4.In particular, it is necessary to shorten the time it takes for the outlet boat 62 to switch from the drain port 64 to the pressure port 3. becomes.

In order to shorten the switching time or improve the response speed of the solenoid valve, (1) Reduce the size of the spool 1050 to reduce its weight. (2) Increase the responsiveness of the solenoids 108 and 109.

(3) Shorten the moving distance of the spool 105, that is, the stroke.

However, regarding (1) above, if the spool is made smaller, the maximum flow rate will be smaller, so it is necessary to increase the pressure of the pressure source to ensure the maximum flow rate, and the equipment cost of the pressure source and piping system will be increased. The problem is that it is expensive. Regarding (2) above, it is necessary to increase the voltage applied to the solenoid, but this increases the heat generation in the solenoid, resulting in greater energy loss and the risk of burning out the solenoid. The problem is that there are limitations.

An object of the present invention is to shorten the switching time of the electromagnetic valve 4 by shortening the stroke of the spool 105 in connection with the above (31), thereby achieving precise control of the combustion injection timing.

FIGS. 9 and 10 show the general configuration of a solenoid valve. The solenoid valve 4 includes a pair of left and right solenoids 108, 109 and a switching valve 110. In the solenoids 108 and 109, plungers 102 and 104 are guided in the axial direction in casings 111 and 112, and coils 101 and 103 are attached to the circumferences U of the plungers 102 and 104, respectively. Switching valve 11
0, the spool 105 is guided in the axial direction within the casing 113. The spool 105 is connected to the left and right plungers 102, 104, so when the right coil 101 is excited, the spool 105 is connected to the plunger 102, 104.
02 and moves to the left, and the outlet boat 62 and pressure port 3 are communicated with each other. On the other hand, when the left coil 103 is excited, the plunger 104 moves to the right, and the outlet boat 62 and drain boat 64 are brought into communication. FIG. 9 shows a state in which the left solenoid 109 is energized, and FIG. 10 shows a state in which the right solenoid 108 is energized.

In the above structure, the positions of the respective boats are selected so that the pressure port 3 opens only after the drain boat 64 is completely closed by the spool 105, so the stroke of the spool 105 becomes longer and the electromagnetic There is a problem in that the time required for switching the valve 4 is limited. Another possibility is to shorten the stroke of the spool while maintaining the pressure loss in the valve by reducing the width of the boat and increasing the diameter of the spool to secure the opening area of the boat, but in this case, the weight of the spool is There is a problem in that the time required for switching becomes longer as the number of times increases.

The embodiment of the present invention described in connection with FIG. 11 and FIG. This is characterized in that the stroke of the spool 105 is shortened by selecting the position of the boat so as to communicate with each other, thereby shortening the time required to switch the solenoid valve. In the conventional configuration, where b is the stroke of the spool 105, b is greater than 2a with respect to the width a of the pressure port 3 and the drain boat 64. However, the embodiment of the present invention related to FIGS. 11 and 12 For a<b<2
Since a and -at~ are obtained, the switching time of the solenoid valve 4 can be shortened to approximately one-half at the maximum. 13 and 14 are enlarged views for comparing the relationship between the outlet port 62 of the switching valve 110, the pressure port 3, the drain boat 64, and the spool 105 in FIGS. 9 to 12. 13 is related to FIGS. 9 and 10, and FIG. 14 is related to FIGS. 11 and 12 according to the present invention. The width is 1050, and b is the spool with 1050 strokes. In this case, as shown in FIG. 14, pressure oil leaks from the pressure port 3 to the drain boat 64 due to temporary communication during switching between the pressure port 3 and the drain boat 64, causing energy loss, but the switching time of the solenoid valve 4 is short. Therefore, the amount is small.

For example, differential pressure "t/cr! When the spool of a solenoid valve with a flow rate of 80 t/mi□ operates at a speed of 3 m/B6c, if the time during which the boat is temporarily connected is one half of the switching time, then the pressure oil Loss energy W due to leakage can be expressed by the following equation.

Here, P is the differential pressure ('9/1yn2), and Q is the flow rate (l
//rrlin), E is the communication time, which is doubled because the communication occurs twice due to the reciprocation of the spool. to is the cycle period of the spool, and 1/lo is the number of round trips of the spool in one second. P amount is a unit of horsepower. Here, in a 4-cycle engine with a rotational speed of 600 rpm, '/lo = 600/60 X1/2 = 5, so the value of W in the above equation is as follows. This lost energy reduces engine cylinder horsepower by 75
If it is 0Pf, it is only 0.4%, which is a negligible value.

In the embodiment of the present invention, the respective opening areas of the pressure port 3 and the drain boat 64 are selected such that the drain boat 64 is relatively small with respect to the pressure port 3,
By increasing the orifice in the drain boat, the amount of leaked oil can be reduced while maintaining the accuracy of fuel injection timing control.

For example, a radially annular drain boat provided on the inner surface of the casing 113 that guides the spool 105 may be provided not around the entire circumference but around half or a quarter of the circumference, or a restriction υ may be provided in the return conduit 76. For example, although the time for which the outlet boat 62 is released to the atmospheric pressure of the tank 58 becomes slightly longer, the amount of leaked oil can be significantly reduced. That is,
If the drain boat 64 is a one-eighth boat and the pressure boat is a full-circle boat, the pressure port 3 and the drain boat 64
Since the size of the throttle when the drain boat 64 communicates is almost determined by the opening area of the drain boat 64, the energy loss due to the amount of leaked oil is reduced to about one-eighth of the above amount.

The operation will be explained. In the state shown in FIG. 11 in which the left solenoid 109 is energized and the right solenoid 108 is deenergized by the electric signal from the control circuit 8, the outlet boat 62 is in communication with the drain boat 64. , the pressure port 3 is shut off. When the internal combustion engine rotates and injection timing is reached, the left solenoid 109 is deenergized and the right solenoid 108 is energized by a signal from the control circuit 8. Spool 105 is solenoid 10
The outlet port 62 is forced to the left by the force 8 and communicates with the pressure port 3, resulting in the state shown in Figure 12. Pressure oil is supplied from the pressure port 3 to the servo pressure chamber 21 of the fuel valve 3 via the outlet boat 62, so the servo piston 17 descends and fuel injection is performed.

Next, when the fuel injection is completed and the state shown in FIG. 12 is switched to the state shown in FIG. 11, the left solenoid 109 is energized and the right solenoid 108 is deenergized. In this case, the spool 105 is biased to the right and passes through a temporary communication state between the pressure port 3 and the drain boat 64, and then passes through the outlet boat 6.
2 communicates with the drain boat 64 to reach the state shown in FIG. 11, but since the drain boat is relatively constricted, the amount of outflow is limited, and the time required for the pressure of the outlet boat 62 to drop is slightly longer. However, since fuel injection has been completed, the responsiveness in this case does not affect the controllability of the engine.

As described above, in the solenoid valve according to the present invention with 1-, when the spool 105 moves, the pressure port 3 and the drain boat 6
By selecting the position of the boat so that the ports 4 and 4 are temporarily in communication, it is possible to shorten the stroke of the spool 105, and the problem caused by temporary communication, that is, leakage of pressure oil from the pressure port 3 to the drain boat 64, can be reduced. This problem is solved by restricting the amount of oil to a small amount by relatively narrowing the opening area of the drain boat 64.
This shortens the operating time and enables more accurate control of injection timing.

As described above, according to the present invention, it is possible to easily adjust the fuel injection timing, injection amount, and injection pressure without temporarily stopping the internal combustion engine. Since the pump piston 18 of the fuel valve 3 is driven by the servo piston 17 having a larger diameter, the injection pressure can be made high, and furthermore, the throttle member 19, 88, 90 is provided on the drain side of the fuel. Therefore, the pressure in the pump chamber 33 of the fuel valve 3 can be made high, and therefore, the amount of vI4 can be precisely controlled without being affected by frictional force, etc., and reliability is improved.

Furthermore, since the electromagnetic valves 4, 7, and 91 are used, complicated drive mechanisms such as conventional cams, camshafts, and advance angle devices are not required, so it can be realized at low cost.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an embodiment of a fuel valve 3 according to the present invention, and FIG. 3 explains the principle of an embodiment of the present invention. FIG. 4 is a configuration diagram showing another embodiment of the present invention, FIG. 5 is a sectional view showing another embodiment of the fuel valve 3 according to the present invention, and FIG. 6 is a diagram showing the fuel valve 3 according to another embodiment of the present invention.
7 is a block diagram showing still another embodiment of the present invention, FIG. 8 is a block diagram showing still another embodiment of the present invention, and FIG. 9 is a general diagram. FIG. 10 is a cross-sectional view showing another operating state of the solenoid valve 4 shown in FIG. 9, and FIG. 11 is a cross-sectional view of the solenoid valve 4 according to another embodiment of the invention. 12 is a sectional view showing another operating state of the solenoid valve 4 shown in FIG. 11, FIG. 13 is a partially enlarged view of FIGS. 9 and 11.10, and FIG. 141 is a partially enlarged view of FIG. , is a partially enlarged view of FIG. 12. 1-...First pressure source 2...Second pressure source 3...Fuel valve 4,7.91...Solenoid valve 8...Control circuit 12
... Automatic injection nozzle 17 ... Servo piston 18
... Pump piston 19,88.90... Throttle member 21... Servo pressure chamber 33... Pump chamber 49.
...Control conduit 55...Pressure conduit 76...Return conduit 62...Outlet port 63...Pressure boat 64.
...Drain boat 101.103...Coil 102
, 104... plunger 105... spool 1
08,109...Solenoid 110...Switching valve application Person Kawasaki Heavy Industries Co., Ltd. agent Yujibe Takashi, patent attorney ゛N9 Diagram LQ 10th! Q Figure 11 Figure 12 Continuation of page 1 0 Inventor: Tadanori Higashi Inside the Kobe Factory of Higashi J Company, Chuo-ku, Kobe City 0 Inventor Osamu Sato - Inside the Kobe Factory of Higashi J Company, Chuo-ku, Kobe City [Isaki 3-1-1 Kawasaki Heavy Industries Co., Ltd. [3-1 Saki-cho
Chome 1-1 Kawasaki Heavy Industries Co., Ltd. Procedural Amendment (Voluntary) 1: Indication of the case Relationship with Patent Application No. 1454535 of 1980 Patent applicant 4, Agent 103 6, Inventions increased by amendment Number 7, Drawings subject to correction (Fig. 1, Fig. 4, Fig. 7, Fig. 8) 8. Contents of correction - Loli 7

Claims (1)

[Claims] A pump chamber 3 in which the pump piston 18 of the mff1R valve 3 is driven by a servo piston 17 having a larger diameter and defined by one end surface of the pump piston 18.
3 is connected to an automatic injection nozzle 12 with a shutoff valve, the first pressure source 1 supplies fuel to the pump chamber 33 via the first electromagnetic valve 7, while the second pressure source 2 and the servo piston 1
A second electromagnetic valve 4 is provided between the servo pressure chamber 21 and the servo pressure chamber 21 defined by one end surface of the servo pressure chamber 21 .
The second solenoid valve 4 of the fuel injection device is capable of controlling whether the second solenoid valve 4 is connected to the second pressure source 2 or to the drain oil side via the throttle member 19. When the servo pressure chamber 21 is switched from the oil drain side to the second pressure source 2, the positions of the respective boats are determined so that the pressure boat and the drain port temporarily communicate with each other during the switching of the solenoid valve 4. (2) The first electromagnetic valve 7 and the second electromagnetic valve 4 are integrally configured. A fuel injection control device for an internal combustion engine according to claim 1, characterized in that: