JPH0118254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device, and more particularly, to a fuel injection device.
The present invention relates to a fuel injection device configured such that fuel injection start timing and fuel injection end timing can be independently controlled by separate adjustment members.

In general, in order to improve the fuel efficiency of diesel engines, reduce the content of harmful components in exhaust gas, and adapt to various types of fuel, the injection timing of a fuel injection pump is configured to be variable. It is hoped that

By the way, in order to change the injection timing of the fuel injection pump according to the engine speed, it is sufficient to change the phase between the camshaft of the fuel injection pump and the drive shaft of the engine, and a so-called automatic device is used for this purpose. Tick timers are widely used. However, as described above, this known timer has a configuration in which the phase between both shafts is relatively displaced according to the rotation speed, so the camshaft of the pump is placed on the engine side, as in the case of conventional single cylinder fuel injection pumps for ships. In addition to being unsuitable for such a structure, it also has the problem that the injection system cannot be controlled solely by adjusting the fuel injection pump.

As a means to solve this problem,
As seen in Publication No. 49-68117 and Publication of Utility Model Application No. 52-80317, etc., a double plunger mechanism is adopted,
In addition to the injection amount adjustment rack that adjusts the fuel injection end timing, a timing adjustment rack that is installed separately and independently to adjust the fuel injection start timing is provided, allowing injection only by adjusting the fuel injection pump side. Fuel injection pumps have been proposed that are configured to have variable timing.

However, this proposed fuel injection pump has a drawback in that when the position of the timing adjustment rack is changed, the injection amount also changes accordingly. This change in injection amount appears as a change in engine speed, which is corrected by the governor.

Therefore, in this proposed pump, the injection timing and fuel injection amount are controlled by a fuel injection start timing adjustment member provided on the fuel injection pump side and a separate fuel injection end timing adjustment member independent from the fuel injection start timing adjustment member. Each can be adjusted independently, but the configuration is such that the change in injection amount due to injection timing control is corrected by the governor when it occurs as a change in the actual injection amount, so the responsiveness of the control is The problem is that the fuel consumption is low and good fuel control cannot be performed.

Therefore, it is an object of the present invention to provide a fuel injection device configured to independently control the fuel injection start timing and fuel injection end timing by separate adjustment members, in which the response of fuel control is improved. An object of the present invention is to provide a fuel injection device that can significantly improve performance.

Hereinafter, the present invention will be explained in detail using an example in which the present invention is applied to a marine diesel engine.

Referring to FIG. 1, an embodiment is shown in which a multi-cylinder marine diesel engine 1 is equipped with a number of single-cylinder marine fuel injection pumps corresponding to the number of cylinders. 2, only two fuel injection pumps 2, 3 are shown. These fuel injection pumps are each driven by a cam provided in the diesel engine 1 to pressurize fuel supplied via an oil supply system (not shown), and the pressurized fuel from each fuel injection pump is delivered to the injection pipe 4. , 5 to the corresponding cylinder. In order to adjust the injection amount Q and injection timing (injection advance angle) of the fuel fed by the fuel injection pump, a first rack 6 for adjusting the injection amount and a second rack 7 for adjusting the injection timing are used for each fuel. The racks 6 and 7 are provided in common to the injection pumps 2 and 3, and are configured to be driven by the corresponding first actuator 8 and second actuator 9. Reference numeral 10 indicates a control unit for driving and controlling the first and second actuators 8 and 9, and the control unit 10 controls the first and second actuators 8 and 9 according to a control signal (described later) from the control unit 10.
Then, the second actuators 8 and 9 are operated, and the positions of the first rack 6 and the second rack 7 are adjusted, respectively, so that each fuel injection pump is operated with a fuel injection amount and injection timing that match the operating condition of the diesel engine. It is becoming more and more like this.

FIG. 2 shows a sectional view of the fuel injection pump 2 of FIG. 1. As shown in FIG. The fuel injection pump 2 has a casing 11 fixed to the case 1a of the diesel engine 1 with bolts or the like.
A plunger barrel 13 having a delivery valve 12 at one end is disposed therein. A double plunger 16 consisting of a metering plunger 14 and a timing plunger 15 is fitted in the plunger barrel 13, and is driven by a resilient coil spring 18 housed in a spring chamber 17 in the casing 11. A flange portion 16a at the lower end of the double plunger 16 is urged downward. The double plunger 16 is configured such that the metering plunger 14 and the timing plunger 15 can rotate independently of each other in their circumferential direction, but move simultaneously in their axial direction. Accordingly, as the cam 19 within the diesel engine 1 rotates, these plungers 14, 15 can reciprocate simultaneously in the axial direction. A metering sleeve 20 for adjusting the rotational position of the metering plunger 14 and a timing sleeve 21 for adjusting the rotational position of the timing plunger 15 are coaxially provided on the outside of the double plunger 16. The metering sleeve 20 is connected to the metering plunger 1.
4, but is connected to the metering plunger 14 so as not to restrict the axial movement of the metering plunger 14. On the other hand, the timing sleeve 21 rotates together with the timing plunger 15, but is coupled to the timing plunger 15 so as not to restrict the movement of the timing plunger 15 in the axial direction. A first rack 6 and a second rack 7 passing through the casing 11
are engaged with the pinion portion 22 of the metering sleeve 20 and the pinion portion 23 of the timing sleeve 21, respectively, and by adjusting the positions of the first rack 6 and the second rack 7, the corresponding plungers 1
4, 15 rotational positions can be adjusted.

Suction and exhaust holes 26 and 27 are provided in the plunger barrel 13 in correspondence with notches 24 and 25 formed at the upper ends of each plunger 14 and 15, respectively. The double plunger 16 is at its maximum lowered position (state shown in Figure 2)
When the suction/discharge hole 26 is in the metering plunger 14
Since the suction/discharge hole 27 faces the notch 25, the fuel is not pressurized within the high pressure chamber 28 even if the double plunger 16 begins to rise. When the double plunger 16 rises further and the intake/discharge hole 27 is blocked by the side wall of the timing plunger 15, fuel starts to be pressurized within the high pressure chamber 28, and the pressurized fuel passes through the delivery valve 12. It is delivered to the injection pipe through the injector. When the double plunger 16 continues to rise further and the intake/discharge hole 26 faces the notch 24, fuel injection ends.

FIG. 3 shows a characteristic curve a showing the decrease in the injection amount determined by the position La of the first rack 6 for timing, and a characteristic curve b showing the decrease in the injection amount determined by the position Lb of the second rack 7 for metering. is shown. From the characteristic curve shown in Fig. 3, for example, La,
When Lb is L ₁ and L ₂ respectively, the injection amount is (Q ₂ −
_Q1 ).

Although one fuel injection pump 2 has been described above, the other fuel injection pumps are similarly configured, and the injection amount and injection timing of these fuel injection pumps can be simultaneously controlled by adjusting the positions of the racks 6 and 7. can do.

Furthermore, although an embodiment in which the present invention is applied to a single-cylinder fuel injection pump for ships has been described based on FIGS. 1 to 3, the application of the present invention is not limited to single-cylinder fuel injection pumps for ships. It goes without saying that the present invention can also be applied to, for example, a row-type fuel injection pump for vehicles.

FIG. 4 shows a block diagram of the fuel injection control system of the apparatus shown in FIG. Rotation speed setting device 3 for setting the rotation speed of the diesel engine 1
a set rotation signal S ₁ indicating the set rotation speed Ns from 1;
Diesel engine 1 output from rotation sensor 32
The actual rotational speed signal _S2 indicating the actual rotational speed Na is
It is input to the injection amount calculation circuit 33. Here Ns=
The injection amount necessary to obtain the calculated injection amount is calculated, and a first calculation output signal _S3 indicating the position of the first rack 6 necessary to obtain the calculated injection amount is output, and a correction circuit 34, which will be described in detail later, outputs a first calculation output signal S3. After the necessary correction is performed, it is output as a correction output signal _S4 , and is sent to the drive circuit 35.
The first control signal C1 is amplified by the first control signal _C1 .
is applied to the actuator 8. Therefore, the first actuator 8 moves the first rack 6 in the fuel increasing direction in accordance with the first control signal _C1 when Na<Ns, and moves the first rack 6 in the fuel increasing direction when Na>Ns.
move in the direction of decreasing fuel. Reference numeral 36 denotes a timing calculation circuit for calculating the appropriate fuel injection timing θ ₀ at any given time based on information from a predetermined sensor according to the operating state of the engine. In the illustrated embodiment, the actual rotational speed signal S ₂ from the rotation sensor 32, the pressure sensor 3 that detects atmospheric pressure,
The pressure signal S ₅ from 7, the temperature signal S ₆ from the temperature sensor 38 for detecting the fuel temperature, and the type signal S 7 from the fuel type setting device ₃₉ that generates a signal indicating the type of fuel to be used are used in the calculation. The timing calculation circuit 36 calculates the optimum timing θ ₀ based on the information contained in these signals. Then, a second calculation output signal _S8 indicating the position of the second rack 7 required to obtain the timing θ ₀ of this calculation result is outputted from the calculation circuit 36. The second calculation output signal _S8 is amplified by the drive circuit 40 and then applied to the second actuator ₉ as a second control signal C2, and the position of the second rack 7 becomes a position that provides the desired timing _θ0 . controlled as follows. The second calculation output signal _S8 is also input to the correction circuit 34, and the first calculation output signal _S3 is corrected in the correction circuit ₃₄ in accordance with the change in the second calculation output signal S8. This correction is to electrically give in advance the influence that the change in injection timing that occurs in accordance with the change in the second calculation output signal _S8 has on the injection amount adjustment system via the mechanical system. The responsiveness of the system can be significantly improved.

According to such a configuration, the position of the first rack 6 is controlled by the first actuator 8 so as to maintain the rotation speed set by the rotation speed setting device 31, while the second rack 7 is controlled in position by the timing calculation circuit 3.
The position is controlled by the second actuator 9 to achieve the optimum timing calculated in step 6. As explained in Fig. 3, when the position of the second rack 7 is adjusted and the injection timing changes, the injection amount also changes accordingly, but this change in the injection amount results in a change in the rotational speed. Feedback is provided to the injection amount control system via the sensor 32, and the second calculation output signal _S8 is previously input to the correction circuit 34.
Therefore, even if the injection timing is adjusted, the injection amount is controlled independently of the timing control, and the injection amount cannot be controlled to a predetermined value with extremely high responsiveness regardless of the timing control. can. The above-mentioned speed regulating operation performed by the first actuator 8 is performed electronically, so it is extremely easy to widen the operating range, and it can be done with a small device, so the device can be miniaturized. It is also possible. Furthermore, the injection timing can be adjusted over a wide range with precision.
It has the advantage that not only can fuel efficiency be significantly improved, but also inferior oil can be burned efficiently.

In the above embodiment, control was performed using the rotational speed, atmospheric pressure, and fuel temperature as parameters indicating the operating state of the engine, but the device of the present invention is not limited to these parameters, and can also be controlled using other parameters. may be added, or some of the above parameters may be omitted.

FIG. 5 shows a block diagram of another embodiment of the fuel injection control system. In the control system shown in FIG. 5, rack position sensors 41 and 42 are used to detect the position of each rack. A first position signal S ₉ indicating the position of the first rack 6 and a second position signal S indicating the position of the second rack 7 detected by each of these rack position sensors 41 and 42 are provided. This control system differs greatly from the control system shown in FIG. 4 in that signal ₁₀ is used as a feedback signal. In FIG. 5, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and explanations thereof will be omitted. The target injection amount calculation circuit 43 operates the rotation setting device 3 based on each signal from the rotation speed setting device 31, the rotation speed sensor 32, the pressure sensor 37, and the temperature sensor 38.
A first target signal S indicates the position of the first rack 6 required to obtain the calculated injection amount. Outputs ₁₁ . The first target signal _S11 is inputted to the other input of the error calculation circuit 44, which has the first position signal _S9 inputted to one input, and here, the target position and the actual position of the first rack 6 are inputted. A first error signal _S12 indicating this difference is sent to the first actuator ₈ as a first control signal C3 via a correction circuit 34 and a drive circuit 35.
is applied to Therefore, the first actuator 8
is driven so that the first error signal _S12 becomes zero,
As a result, the position of the first rack 6 is determined by the first target signal.
The positioning is controlled to the position indicated by _S11 .

On the other hand, the target timing calculation circuit 45 includes a rotation speed sensor 32, a pressure sensor 37, and a temperature sensor 3.
8. Each signal from the fuel type setting device 39 and the first target signal _S11 are inputted, and based on these input signals, an appropriate injection timing is calculated for the operating state of the engine at the time. A second target signal _S13 indicating the position of the second rack 7 required to obtain the calculated injection timing is output. 2nd target signal S ₁₃
and the second position signal _S10 are input to an error calculation circuit 46, which outputs a second error signal _S14 according to the difference between the second rack position indicated by the second target signal _S13 and the actual second rack position. Ru. The second error signal S ₁₄ is applied to the second actuator 9 as a second control signal C ₄ via the drive circuit 40 and is also input to the correction circuit 34 . Second actuator 9
is driven by the second control signal _C4 so that the second error signal _S14 becomes zero, and the second rack 7 is controlled to be positioned at the position indicated by the second target signal _S13 . The operation in which the injection amount control system corrects the change in the injection amount caused by controlling the second rack 7 is the same as the operation in the case of the control system shown in FIG.

According to the control circuit shown in FIG. 5, since the rack position information is fed back, even more accurate control can be performed. In this case as well, the signals indicating the operating state of the engine are not limited to those shown in FIG. 5, as in the case of the embodiment shown in FIG.

According to the present invention, as described above, the injection timing adjustment member for adjusting the fuel injection start time without changing the fuel injection end time and the fuel injection end time provided separately from the injection timing adjustment member are provided. In a fuel injection device configured such that the fuel injection amount and fuel injection timing can be independently controlled by an injection amount adjustment member for adjustment, the fuel injection amount that would be generated by adjusting the fuel injection timing. Since it is possible to correct changes in the amount of fuel in an extremely responsive manner prior to such changes actually occurring, highly accurate fuel control is possible, and excellent effects are achieved in improving fuel efficiency and purifying exhaust gas.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view showing the configuration of an embodiment of the present invention, FIG. 2 is a sectional view of the fuel injection pump of FIG. 1, FIG. 3 is a characteristic curve diagram of the fuel injection pump of FIG. 2, 4 is a block diagram of the control section of the fuel injection system of the apparatus shown in FIG. 1, and FIG. 5 is a block diagram showing another embodiment of the control section of the fuel injection system of the apparatus shown in FIG. 1... Diesel engine, 2, 3... Fuel injection pump, 6... First rack, 7... Second rack, 8
...First actuator, 9...Second actuator, 10...Control unit, 13...Plunger barrel, 14...Measuring plunger, 15...
Plunger for timing, 16... Double plunger, 20... Sleeve for metering, 21... Sleeve for timing, 24, 25... Notch, 26, 2
7... Suction and exhaust hole, 31... Rotation speed setting device, 32...
Rotation sensor, 33... Injection amount calculation circuit, 36...
Timing calculation circuit, 43...Target injection amount calculation circuit, 44, 46...Error calculation circuit, 45...Target timing calculation circuit, _S1 ...Setting rotation signal, _S2 ...
... Actual rotation speed signal, S ₃ ... First calculation output signal, S ₈ ...
...Second calculation output signal, S ₉ ...First position signal, S ₁₀
...Second position signal, S ₁₁ ...First target signal, S ₁₂ ...
...First error signal, S ₁₃ ...Second target signal, S ₁₄ ...
Second error signal, C ₁ , C ₃ ...First control signal, C ₂ ,
C ₄ ...Second control signal.

Claims (1)

[Claims] 1. An injection timing adjustment member for adjusting the fuel injection start time without changing the fuel injection end time, and an injection provided separately from the injection timing adjustment member for adjusting the fuel injection end time. A fuel injection device driven by an internal combustion engine and configured to be able to adjust a fuel injection start timing and a fuel injection end timing independently of each other, including a quantity adjusting member, wherein a desired target rotation speed of the internal combustion engine is provided. a sensor that outputs a rotational speed signal indicating the rotational speed of the internal combustion engine; and the injection timing that responds to at least the rotational speed signal and provides a target injection start timing that is compatible with the operating state of the internal combustion engine. means for outputting an injection timing control signal indicating the position of the adjustment member; means for adjusting the position of the injection timing adjustment member to a position where the target injection start timing is obtained in response to the injection timing control signal; outputting an injection amount control signal indicating a position of the injection amount adjusting member necessary to rotate the internal combustion engine at the target rotation speed in response to the number signal and an electric signal output from the setting means and indicating the target rotation speed; and a means for correcting the injection amount control signal in response to the injection timing control signal to obtain a fuel injection end timing that corresponds to the injection start timing that is targeted at that time and is necessary to ensure the target injection amount. 1. A fuel injection device comprising: a correction means for adjusting the position of the injection amount adjusting member; and a means for adjusting the position of the injection amount adjusting member in response to an output of the correction means.