JP3548712B2 - Diesel engine fuel metering device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel metering device for a diesel engine.
[0002]
[Base technology of the invention]
The present invention is based on the following technology.
That is, as shown in FIG. 1, a fuel injection pump (1) and an electronic governor (3) are provided, the fuel injection pump (1) is provided with a fuel metering section (4), and the electronic governor (3) The apparatus includes a rotational speed setting means (9), an actual rotational speed detecting means (11), an actual adjustment amount position detecting means (12), a controller (8), and an actuator (27). As shown in FIG. ) Sets an isochronous control line (26) by PID control that maintains the target rotation speed at a constant value regardless of the engine load, and the electronic governor (3) sets the target rotation speed, the actual rotation speed, and the actual adjustment position. A fuel metering device for a diesel engine that performs isochronous control based on an isochronous control line (26) based on the detection of (i).
[0003]
[Prior art]
Conventionally, in this type of apparatus, as shown in FIG. 5, even when the target rotation speed of the electronic governor (3) is reduced from a predetermined high speed rotation (15) to a predetermined low speed rotation (16), The isochronous control based on the isochronous control line (26) is performed.
[0004]
[Problems to be solved by the invention]
The above prior art has the following problems.
That is, in the above case, as shown by the rotation speed-actual adjustment amount position curve (135) in FIG. 5, while the actual rotation speed decreases, the actual adjustment amount position is shifted from the fuel non-injection position (17) by a predetermined amount. It reaches the minimum metering area (A) up to the fuel increasing position (18). Then, actual rotational speed while hunting increased before and after the target speed (16), converges to the target rotational speed (16). Therefore, the settling time of the rotation is long, and the response of the control is low.
The reason is as follows. That is, in the above case, if the isochronous control is always performed, the PID control is started early, and the integral value is unnecessarily increased. Therefore, in order to set the actual rotation speed to the target rotation speed (16), it is necessary to overshoot the actual rotation speed from the target rotation speed in order to cancel the increased integral value. It takes time to converge on the target rotation speed (16).
[0005]
An object of the present invention is to provide a fuel metering device for a diesel engine that can solve the above problems.
[0006]
[Means for Solving the Problems]
The configuration of the present invention is as follows.
In the above base technology,
As shown in FIG. 2, the controller (8) can set a droop control line (19) by P control for decreasing the target rotation speed as the engine load increases, and this droop control line (19) is used for isochronous control. Cross line (26),
[0007]
When the target rotation speed of the electronic governor (3) is reduced from a predetermined high-speed rotation speed (15) to a predetermined low-speed rotation speed (16), the actual adjustment position is shifted from the fuel-free injection position (17) to a predetermined rotation speed. When reaching the minimum metering area (A) up to the fuel increasing position (18), the controller (8) sets the droop control line (19), and the electronic governor (3) sets the droop control line (19). Performs droop control based on
[0008]
The actual metering position is in the small metering area (B) on the fuel reduction side from the predetermined metering position (33) corresponding to the intersection (34) of both control lines (19) and (26), and The electronic governor (3) maintains the droop control while the actual rotational speed is within the medium / high-speed rotational speed area (C) which is equal to or higher than the target rotational speed (16) of the electronic governor (3),
When the actual adjustment amount position exceeds the small adjustment amount area (B), or when the actual rotation speed falls below the medium / high speed rotation area (C), the controller (8) switches the droop control line (19). A fuel metering device for a diesel engine, wherein the electronic governor (3) performs the isochronous control based on the isochronous control line (26).
[0009]
Function and effect of the present invention
The present invention has the following effects.
As shown in FIG. 2, when the target rotation speed of the electronic governor (3) is reduced from a predetermined high rotation speed (15) to a predetermined low rotation speed (16), the rotation speed-actual adjustment amount position curve is obtained. As shown by (35), while the actual rotational speed decreases, the actual adjustment amount position reaches the minimum adjustment amount area (A) from the no fuel injection position (17) to the predetermined fuel increase position (18). Since the droop control is performed before the isochronous control is performed, hunting of the actual rotational speed hardly occurs, and the actual rotational speed converges to the target rotational speed (16) in a short time. Therefore, the settling time of the rotation is short, and the response of the control is high.
The reason is as follows. That is, if the droop control is performed before the isochronous control, the P control is performed based on the proportional value during the droop control, and then the PID control is started from the time of switching to the isochronous control. Growth can be avoided. Therefore, when setting the actual rotational speed to the target rotational speed (16), it is not necessary to cancel the unnecessarily increased integral value, and it is not necessary to largely overshoot the actual rotational speed from the target rotational speed (16). Therefore, it does not take long before the actual rotation speed converges to the target rotation speed (16).
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 to FIG. 4 are views for explaining a fuel metering device for a diesel engine according to an embodiment of the present invention. In this embodiment, an example in which the invention is applied to a multi-cylinder diesel engine having a row type fuel injection pump is shown. As shown in FIG. 1, the fuel supply device of the engine includes a fuel injection pump (1), a mechanical governor (2), and an electronic governor (3). The fuel injection pump (1) includes a fuel adjusting section (4) that slides in a fuel increasing / decreasing direction, and the fuel adjusting section (4) is urged by an urging means (5) in a fuel increasing direction. .
[0011]
The configuration of the mechanical governor (2) is as follows.
The mechanical governor (2) includes a governor lever (20), a governor spring (21), and a governor force generating means (22). The governor lever (20) is swingably provided, and is interlockingly connected to a speed control lever (23) via a governor spring (21). The governor spring (21) applies a governor spring force (24) to the governor lever (20) according to the governing setting of the governing lever (23). The governor force generating means (22) faces the governor lever (20) and applies a governor force (25) corresponding to the rotation speed to the governor lever (20). The swinging end of the governor lever (20) serves as a mechanical output section (6). The mechanical output section (6) is connected to a mechanical input section (7) of a fuel metering section (4) to increase its fuel amount. Standing from the side. The mechanical output unit (6) receives the mechanical input unit (7) of the fuel metering unit (4) urged by the urging means (5), and generates a governor spring force (24) and a governor force (25). The fuel metering section (4) is metered and moved by the operation using the unbalanced force.
[0012]
The configuration of the electronic governor (3) is as follows.
The electronic governor (2) includes an electronic actuator (27), a controller (8), a target rotation speed setting unit (9), a target rotation speed detection unit (10), an actual rotation speed detection unit (11), and an actual adjustment amount position detection. Means (12). The electronic actuator (27) is a linear solenoid, and its output rod serves as an electronic output section (13). The electronic output unit (13) faces the electronic input unit (14) of the fuel metering unit (4) from the fuel increasing side. The electronic output unit (13) receives the electronic input unit (14) of the fuel metering unit (4) energized by the urging means (5), and is controlled by the controller (8) to operate the fuel metering unit ( 4) The metering movement is performed.
The configuration of the controller (8) is as follows.
The controller (8) includes a rotational speed PID control unit (28) and a metering position PID control unit (29). A rotation speed PID control unit (28) calculates a rotation speed deviation based on a target rotation speed detection signal from the target rotation speed detection means (9) and an actual rotation speed detection signal from the actual rotation speed detection means (11). Then, a target metering position setting signal is transmitted to the metering position PID controller (29). A metering position PID control unit (29) calculates a metering position deviation based on a target metering position setting signal and an actual metering position detection signal from an actual metering position detecting means (12), and calculates an electronic actuator ( A control output signal is transmitted to 27) to control the operation of the electronic output unit (13). The target speed setting means (9) is also used as a speed control lever (23). The actual adjustment position detecting means (12) is attached to the urging means (5), and detects the position of the output rod (5a) of the urging means (5) following the movement of the fuel adjusting section (4). Thus, the actual adjustment position of the fuel adjustment section (4) is indirectly detected. In FIG. 1, reference numeral (30) denotes a boost compensator, (31) denotes a phase compensator, and (32) denotes an emergency circuit.
[0013]
The control characteristics of the electronic governor (3) and the metering characteristics of the mechanical governor (2) are as follows.
FIG. 2 shows a characteristic diagram of the electronic governor and the mechanical governor. The horizontal axis shows the rotation speed, and the vertical axis shows the metering position. A mechanical adjustment characteristic diagram (33) by the mechanical governor (2) is indicated by a solid line, and an electronic control characteristic diagram by the electronic governor (3) is indicated by a chain line. The mechanical metering characteristic diagram (33) includes a horizontal upper limit metering line (33a) and a sloping full load metering line (33b). The load adjustment line (33b) is inclined downward toward the high rotation side. The electronic control characteristic diagram includes an isochronous control line (26) and a droop control line (19). The isochronous control line (26) is vertical and its upper end extends to the high-speed end of the upper limit adjustment line (33a) of the mechanical adjustment characteristic diagram (33). The droop control line (19) is set when the target speed of the electronic governor (3) is reduced from a predetermined high speed (15) to a predetermined low speed (16), as described later. The isochronous control based on the isochronous control line (26) is performed by PID control, and the droop control based on the droop control line (19) is performed by P control.
[0014]
The functions of the electronic governor (3) and the mechanical governor (2) based on the above characteristics are as follows.
When the target rotation speed of the electronic governor (3) is relatively high, control along the isochronous control line (26) is performed during the electronic control operation by the electronic governor (3), and the electronic output unit (13) performs electronic input. By receiving the unit (14), the mechanical output unit (6) is separated from the mechanical input unit (7), the mechanical governor (2) does not act on the fuel metering unit (9), and the electronic governor (3) is removed. ) To maintain the rotation speed at a constant value.
When the load exceeds the full load, metering is performed along the upper limit metering line (33a), and the mechanical output unit (6) receives the mechanical input unit (7), thereby controlling the fuel injection amount in the electronic control operation. And the electronic output section (13) is separated from the electronic input section (14) so that the electronic governor (3) does not act on the fuel metering section (4). The amount of fuel increase is limited by the mechanical metering operation.
When the target rotation speed of the electronic governor (3) is reduced from a predetermined high rotation speed (15) to a predetermined low rotation speed (16), the controller (8) sets a droop control line (19).
[0015]
The processing functions of the controller (8) are as follows.
FIG. 3 shows a flowchart of the processing of the controller (8). In step S1, it is determined whether or not the actual adjustment position is within the minimum adjustment area (A) from the no fuel injection position (17) to the predetermined increase position (18). As shown in FIG. 2, when the target rotation speed of the electronic governor (3) is reduced from the rated rotation speed (15) to the idle rotation speed (16), the actual adjustment position is within the minimum adjustment amount area (A). Therefore, the determination in step S1 is affirmed, and the process proceeds to step S2. In step S2, a droop control line (19) is set, and in step S3, droop control based on the droop control line (19) is performed. As shown in FIG. 2, the droop control line (19) crosses the isochronous control line (26). Upon completion of the process in the step S3, the process returns to the step S1.
[0016]
Thereafter, when the actual adjustment amount position exceeds the minimum adjustment amount area (A), the determination in step S1 is denied, and the process proceeds to step S4. In step S4, it is determined whether the droop control line (19) is set. In this case, since the droop control line (19) is set, the determination is affirmative, and the process proceeds to step S5. In step S5, the actual metering position is within the small metering area (B) on the fuel reduction side from the predetermined metering position (33) corresponding to the intersection (34) of both control lines (19) and (26). In step S6, it is determined whether or not the actual rotational speed is in the medium / high-speed rotational speed area (C) which is equal to or higher than the target rotational speed (16) of the electronic governor (3). The actual metering position is in the small metering area (B) on the fuel reduction side from the predetermined metering position (33) corresponding to the intersection (34) of both control lines (19) and (26), and As long as the actual rotational speed is within the medium / high-speed rotational speed area (C) which is equal to or higher than the target rotational speed (16) of the electronic governor (3), the determinations in steps S5 and S6 are affirmative, and the steps S1 → S4 → S5 → The cycle from S6 to S3 is repeated, and the droop control in step S3 is maintained.
[0017]
When the actual adjustment amount position exceeds the small adjustment amount area (B), or when the actual rotation speed is lower than the medium / high speed rotation area (C), the determination of at least one of steps S5 and S6 is negative. Then, the process proceeds to step S7. In step S7, the droop control line (19) is released, and in step S8, isochronous control based on the isochronous control line (26) is performed. After the process in step S8, the process returns to step S1.
[0018]
If the target rotation speed of the electronic governor (3) is not set to the low rotation speed, the droop control line (19) is not set, so that the actual adjustment position is within the minimum adjustment area (A). If the determination in step S1 is denied, the determination in step S4 is denied, and in step S7, the cycle up to step S8 is repeated without substantial processing, and the isochronous control is continuously performed. Is
[0019]
FIG. 4 shows control results of the actual rotation speed and the actual adjustment amount position. The solid line indicates the result according to the embodiment of the present invention, and the broken line indicates the result according to the prior art which always performs the isochronous control. When the target rotation speed of the electronic governor (3) is reduced from the rated rotation speed (15) to the idle rotation speed (16), in the embodiment of the present invention, as shown by the actual adjustment amount position curve (35), Unlike the actual adjustment position curve (135) of the technique, hunting hardly occurs, and the convergence time to the target adjustment position is short. Further, in the embodiment of the present invention, as shown by the actual rotational speed curve (36), hunting hardly occurs compared to the actual rotational speed curve (136) of the conventional technique, and the convergence time to the target rotational speed is reduced. Is also short. Specifically, convergence took 3.2 seconds in the case of the prior art, but was reduced to 0.5 seconds in the embodiment of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a fuel supply device for a diesel engine according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing control characteristics of an electronic governor of the apparatus of FIG. 1 and adjustment characteristics of a mechanical governor.
FIG. 3 is a flowchart showing a process performed by a controller of the apparatus shown in FIG. 1;
FIG. 4 is a graph comparing the control results of the apparatus of FIG. 1 and the conventional technique.
FIG. 5 is a diagram corresponding to FIG. 2 of the prior art.
[Explanation of symbols]
(A): very small metering area, (B): small metering area, (C): medium and high speed area, (1): fuel injection pump, (3): electronic governor, (4): fuel metering (8): controller, (9): target rotation speed setting means, (10): target rotation speed detection means, (11): actual rotation speed detection means, (12): actual adjustment position detection means, 15) A predetermined high speed, (16) a predetermined low speed, (17) No fuel injection position, (18) A predetermined fuel increasing position, (19) A droop control line, (26) ... Isochronous control line, (33) ... predetermined adjustment position, (34) ... intersection.

Claims (1)

The fuel injection pump (1) includes an electronic governor (3), the fuel injection pump (1) includes a fuel metering unit (4), and the electronic governor (3) includes a target rotation speed setting means (9). The controller (8) includes a rotational speed detecting means (11), an actual adjustment position detecting means (12), a controller (8), and an actuator (27). The controller (8) maintains the target rotational speed at a constant value regardless of the engine load. It sets the isochronous control line (26) by PID control of the electronic governor (3), based on the detection of the target rotation speed and the actual rotation speed and Micho amount position, isochronous control based on isochronous control line (26) In the diesel engine fuel metering device that performs
The controller (8) enables to set a droop control line (19) by P control for decreasing the target rotation speed as the engine load increases, and the droop control line (19) intersects the isochronous control line (26). Like
When the target rotation speed of the electronic governor (3) is reduced from a predetermined high-speed rotation speed (15) to a predetermined low-speed rotation speed (16), the actual adjustment position is shifted from the fuel non-injection position (17) by a predetermined speed. When reaching the minimum metering area (A) up to the fuel increase position (18), the controller (8) sets the droop control line (19), and the electronic governor (3) sets the droop control line (19). Performs droop control based on
The actual metering position is in the small metering area (B) on the fuel reduction side from the predetermined metering position (33) corresponding to the intersection (34) of both control lines (19) and (26), and The electronic governor (3) maintains the droop control while the actual rotational speed is within the medium / high-speed rotational speed area (C) which is equal to or higher than the target rotational speed (16) of the electronic governor (3),
When the actual adjustment amount position exceeds the small adjustment amount area (B), or when the actual rotation speed falls below the medium-high rotation speed area (C), the controller (8) changes the droop control line (19). A fuel metering device for a diesel engine, wherein the electronic governor (3) cancels and performs isochronous control based on the isochronous control line (26).

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