JP4359254B2 - Fuel injection system - Google Patents

Description

  The present invention relates to a follow-up relationship between a throttle operation in a fuel injection system and a target rotational speed that is an ECM command value.

Conventionally, a fuel injection system that drives and controls a fuel injection pump that injects fuel into a cylinder of a diesel engine, a hydraulic timer unit that changes the phase of fuel injection timing, a governor that adjusts the fuel injection amount, and the like is there. An example of such a conventional fuel injection system is described in Patent Document 1 below. In such a fuel injection system, for example, an ECM, which is an example of a control unit of the fuel injection system, calculates a target rotational speed that is one of command values for controlling the engine rotational speed based on a throttle instruction value. It is carried out. For example, the target engine speed corresponding to the throttle command value is stored in advance in the ECM, and the ECM controls the engine speed based on this. By the way, there is the following problem when the throttle command value and the target rotational speed are simply made to correspond one-to-one. For example, when the engine is under load, such as when the ship is sailing, if the sudden operation to increase the throttle is performed, the target speed will increase greatly in a short time, The deviation from the engine speed (hereinafter referred to as “actual engine speed”) becomes large. At this time, the ECM performs processing for rapidly increasing the fuel injection amount and increasing the engine speed in order to quickly eliminate this large deviation. However, a follow-up delay due to the load occurs and the actual engine speed increases. Since it takes time, problems such as discharging a large amount of unburned fuel occur. Therefore, conventionally, in order to solve such a problem, as shown in FIG. 3, a target value filter 61 for performing a filtering process called “smoothing process” is provided between the throttle instruction value and the target rotational speed. The “smoothing process” is a filter process that smoothes or weakens the change in the target rotational speed with respect to the change in the throttle instruction value. As an example of the “annealing process”, after the target rotational speed is tentatively determined based on the correspondence relationship between the throttle instruction value and the target rotational speed described above, the tentatively determined target rotational speed is applied to the throttle operation. A value obtained by multiplying a control coefficient that becomes a delay element is output as a final target rotational speed. That is, the target value filter 61 is an example of a control coefficient serving as the delay element, and is one of the coefficients used for the arithmetic processing performed by the ECM. Then, the target rotational speed that is the output of the target value filter 61 is input to the control object 62 such as a rack or a hydraulic timer unit.
JP 2004-218636 A

  By the way, when there is no load, unlike the case where the load is applied, the follow-up delay due to the load is small, and the response of the change in the actual engine speed due to the throttle operation is good. Therefore, when a sudden operation is performed to increase the throttle when there is no load, the actual engine speed immediately reaches the target speed, contrary to when the load is applied, but overshoot or black smoke occurs. There was a problem such as discharging. As a cause of this problem, since the target value filter 61 has conventionally been determined only with a value that achieves good combustion under a load on the engine, it has not been dealt with at no load. It is. Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel injection system that can cope with a load or no load.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

According to claim 1, in a fuel injection system having a control means for performing a filter process when calculating a target engine speed based on a throttle instruction value, for no load for performing a filter process corresponding to no load And a load coefficient for performing a filter process corresponding to a load applied. The filter process using the no-load coefficient is performed up to the target rotational speed than the filter process using the load coefficient. The arrival time is set so as to be delayed , and comprises a coefficient selection means for selecting either the no-load coefficient or the load coefficient according to the presence or absence of a load.

  As effects of the present invention, the following effects can be obtained.

According to the configuration of claim 1, in the fuel injection system including the control means for performing the filter process when calculating the target engine speed based on the throttle instruction value, the no-load for performing the filter process corresponding to the no-load condition And a load coefficient for performing a filter process corresponding to when a load is applied, and the filter process using the no-load coefficient is up to the target rotational speed than the filter process using the load coefficient. It is set so that the arrival time is delayed, and is equipped with coefficient selection means for selecting either the no-load coefficient or the load coefficient according to the presence or absence of a load , so that a load is applied as in the past. In addition to the filter control coefficient that realizes good combustion in the state, a new control coefficient (coefficient for no load) that can realize proper combustion even when there is no load is provided. By selecting the control coefficient depending on the presence or absence of the load, the fuel injection amount can be prevented from being discharged much black smoke to the outside air or the like, such as overshoot beyond the target value.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following best mode for carrying out the present invention is an example embodying the present invention, and does not limit the technical scope of the present invention. FIG. 1 is a block diagram showing a schematic configuration of a fuel injection system, FIG. 2 is a schematic configuration diagram of a fuel injection pump and related devices, and FIG. 3 is a relationship of information transmission between a throttle instruction value and a target rotational speed. FIG. 4 is a flowchart showing an example of processing for selecting a control coefficient according to the presence / absence of a load, and FIG. 5 shows either a load coefficient or a no-load coefficient as a control coefficient of the target value filter. FIG. 6 is a graph showing an example of the temporal change in the target engine speed when the engine is selected, and FIG. 6 shows the temporal change in the fuel injection amount and the actual engine speed when there is no load. It is the graph which showed an example compared with the case where it is performed.

<Outline configuration>
First, the schematic configuration of the fuel injection system 1 of the present invention will be described with reference to FIG. The fuel injection system 1 described here will be described as a case where the fuel injection system 1 is used as a control system for a fuel injection pump of an engine provided in a ship, for example. However, the same effect can be obtained by using this system. As long as it is adopted, it may be adopted for any kind of thing. As shown in FIG. 1, the fuel injection system 1 is roughly divided into an operation unit 10 and an engine 20. The operation unit 10 is provided in the cab of the ship, and is provided with, for example, a display unit 11, a main throttle 12, a sub throttle 13, and the like. The display unit 11 displays the state of the ship adopting this system, a warning, and the like, and can also issue a warning by voice by incorporating a speaker or the like. The main throttle 12 operates, for example, a throttle valve 29 of the engine 20 and is operated when the ship is in a normal operation state, and is, for example, a lever type. The sub-throttle 13 operates the throttle valve 29 in the same manner as the main throttle 12, but is different from the main throttle 12 in that it is operated when the ship is not in a normal operation state. The shape of the sub-throttle 13 is, for example, a knob type (volume type) switch. Each of the display unit 11 and the main throttle 12 has its own control unit, and communicates with an ECM 21 (Engine Control Module), which is a control unit on the engine 20 side, so that the operation unit 10 and the engine 20 as a whole. Control is in progress. If the communication method such as the protocol is different between the operation unit 10 and the engine 20, a communication repeater 15 is provided for matching the communication method as shown in FIG. The sub-throttle 13 is directly connected to the ECM 21 on the engine 20 side, and the communication system is the same as that on the engine 20 side. The engine 20 is, for example, a diesel engine, and is provided with an ECM 21, a crankshaft rotation speed sensor 22, a camshaft rotation speed sensor 23, a retarding electromagnetic valve 24, an advance electromagnetic valve 25, a rack 28, and the like. The ECM 21 controls an actuator and the like related to the engine 20 based on the state of the operation system such as the sensor related to the engine 20 and the operation unit 10 described above. The crankshaft rotation speed sensor 22 detects the rotation speed of the crankshaft of the engine 20 and outputs the detection result to the ECM 21 as a crankshaft pulse. That is, the rotational speed of the engine 20 can be detected using the crankshaft rotational speed sensor 22. The camshaft rotation speed sensor 23 detects the rotation speed of the camshaft of the engine 20 and outputs the detection result to the ECM 21 as a camshaft pulse. Further, the crankshaft rotation speed sensor 22 and the camshaft rotation speed sensor 23 can be constituted by optical sensors. For example, a predetermined number of marks are provided on the crankshaft, the camshaft itself or gears at predetermined intervals at the time of manufacture. Thus, the ECM 21 can calculate the rotational speeds of the crankshaft and the camshaft 41 by detecting the mark with the optical sensor. The delay angle solenoid valve 24 and the advance angle solenoid valve 25 are used to drive the timer piston of the hydraulic timer unit for changing the cam shaft phase of the fuel injection pump 40 as shown in FIG. It is a hydraulic control valve for controlling the hydraulic pressure to slide to the side. The rack 28 adjusts the amount of fuel injected from the fuel injection pump 40.

<Fuel injection pump>
Next, a schematic configuration of the fuel injection pump 40 and related devices will be described with reference to FIG. The hydraulic timer unit 50 in FIG. 2 is shown in cross section. In particular, for the sake of convenience, the timer piston 52 is shown in a state where it is vertically divided by a one-dot chain line, the state moved to the retard side position is indicated by the timer piston 52a, while the state moved to the advance side position is shown. This is indicated by the timer piston 52b. Of course, the actual timer piston 52 is not divided into two parts by a one-dot chain line as described above, but is integrally formed. In FIG. 2, only the movement state of the timer piston 52 is described. It is divided into two by a one-dot chain line. The fuel injection pump 40 is for pressure-feeding the fuel stored in the fuel tank to an injection nozzle provided in a cylinder of the engine 20, and is driven by a cam shaft 41. A coupling fixing member 42 for fixing the coupling 51 to the cam shaft 41 is fixed. Further, the fuel injection pump 40 is provided with supply ports 43 for supplying fuel to the cylinders of the engine 20, and the example shown in FIG. Further, the fuel injection pump 40 is integrally provided with a governor 30 and a hydraulic timer unit 50. The governor 30 includes the rack 28, and the rack 28 is driven by a proportional solenoid that is driven and controlled by the ECM 21. The hydraulic timer unit 50 is provided with a timer piston 52 that is straight and spline-fitted to the outer peripheral surface of the camshaft coupling 51, and a pump drive gear 53 that is helically spline-fitted to the outer peripheral surface of the timer piston 52. Is provided. The pump drive gear 53 is fixed by a receiving gear 55 that receives a rotational force from the crankshaft of the engine 20 and a bolt 56. Thus, the camshaft 41 can be rotated by the rotation of the crankshaft, and the timer piston 52 is slid in the spline direction of the camshaft coupling 51 (left and right as viewed in FIG. 2). By moving, the phase difference between the camshaft coupling 51 and the pump drive gear 53 can be changed. Here, as already described above, the helical shape of the spline fitting is configured so that the camshaft is retarded by sliding the timer piston 52 to the 52a side and advanced by sliding the timer piston 52 to the 52b side. ing. Further, a space formed on the outer peripheral side of the timer piston 52 fitted with the pump drive gear 53 is a retarded angle chamber 57a, and a space formed on the inner peripheral side of the timer piston 52 fitted with the camshaft coupling 51 is an advanced angle chamber 57b. Respectively. In this case, the timer piston 52 can be slid to the retard side (52a side) by pumping the pressure oil to the retard chamber 57a, while the timer is pumped by pumping the pressure oil to the advance chamber 57b. The piston 52 can be slid to the advance side (52b side). In addition, the retarding solenoid valve 24 and the advancement solenoid valve 25 described above are arranged in the retarding pressure fluid path 58a that leads to the retarding chamber 57a and the advancement pressure oil path 58b that leads to the advancement chamber 57b, respectively. The retard solenoid valve 24 and the advance solenoid valve 25 are controlled and operated by the ECM 21 to feed the pressure oil and slide the timer piston 52. With this configuration, the ECM 21 functions as a control unit that hydraulically controls the timer piston 52 in accordance with the state of the engine 20, and freely delays the phase difference between the crankshaft of the engine 20 and the camshaft 41. It is possible to make an angle or advance.

<Target value filter>
By the way, as already described above, when no load is applied to the engine 20, the response of the change in the actual engine speed due to the operation of the main throttle 12 is good. Therefore, when a sudden operation is performed to increase the throttle at no load, the actual engine speed rapidly reaches the target speed, but overshooting the target speed, discharging black smoke, etc. There was a problem. The cause of this problem is that, as a target value filter 61 (see FIG. 3), conventionally, only a control coefficient that realizes good combustion in a state where the engine 20 is loaded is generally determined. Therefore, in the fuel injection system 1 of the present invention, as the value of the target value filter 61, a no-load coefficient corresponding to no load and a load coefficient corresponding to a load are stored in the ECM 21 in advance. A process of selecting either a no-load coefficient or a load coefficient is performed according to the presence or absence of a load.

<Judgment of presence or absence of load>
Here, an example of processing for selecting a control coefficient according to the presence or absence of a load will be described with reference to FIG. The ECM 21 determines whether or not a load is applied to the engine 20 (S10). The determination in step S10 can be determined by detecting, for example, with a sensor or the like whether or not the clutch connecting the engine 20 and the load side is in the engaged state. When it is determined in step S10 that the engine 20 is loaded, the process proceeds to step S20. On the other hand, when it is determined that the engine 20 is not loaded. Then, the process proceeds to step S30. When the process proceeds to step S20, the ECM 21 selects the above-described load coefficient as the control coefficient of the target value filter 61 (S20). When the process proceeds to step S30, the ECM 21 selects the above-described no-load coefficient as the control coefficient of the target value filter 61 (S30). That is, the ECM 21 also has a function as coefficient selection means for selecting either a load coefficient or a no-load coefficient according to the presence or absence of a load.

<Example of change in target speed>
Here, with reference to FIG. 5, an example of a temporal change in the target rotational speed of the engine 20 when either the load coefficient or the no-load coefficient is selected as the control coefficient of the target value filter 61 will be described. . In FIG. 5, N <b> 1 is a target rotation speed curve at the time of load indicating a temporal change in the target rotation speed of the engine 20 when a load coefficient is selected as the control coefficient of the target value filter 61. On the other hand, N2 is a no-load target rotational speed curve showing a temporal change in the target rotational speed of the engine 20 when the no-load coefficient is selected as the control coefficient of the target value filter 61. Further, FIG. 5 shows that, for example, when the main throttle 12 is at the stop position and the engine 20 is stably idling at the target rotational speed M1 before the time U1, the main throttle 12 outputs 100% at the time U1. It shows the change in the target rotational speed when the target rotational speed is set to M2 when operated to the position for taking out. In this case, the load target rotational speed curve N1 has a sharp rise compared to the no-load target rotational speed curve N2, and the “smoothing process” is performed so that the target rotational speed reaches M2 at time U2. You can see that On the other hand, the no-load target rotational speed curve N2 has a “smoothing process” in which the rising speed is slower than the loaded target rotational speed curve N1, and the target rotational speed reaches M2 at time U3 later than time U2. You can see that it has been applied. From the above, it can be seen that the filter processing that smoothens the change in the target rotational speed with respect to the change in the throttle command value is performed more strongly when there is no load than when the load is applied. That is, the response of the actual engine speed to the throttle operation at no load becomes dull compared to when the load is applied, but a good effect is produced in the following points. This will be described with reference to FIG.

<Other parameter changes>
FIG. 6A shows an example of a temporal change in the fuel injection amount when there is no load, comparing the conventional case with the case where the processing of the present invention is executed. FIG. 6B shows an example of a temporal change in the actual engine speed when there is no load, comparing the conventional case with the case where the processing of the present invention is executed. Also, the time U4 in FIGS. 6 (a) and 6 (b) is the time when the main throttle 12 is operated to a position for outputting 100% from the stop position, for example, similarly to the time U1 in FIG. And In FIG. 6A, G1 shows a conventional fuel injection amount curve which is a temporal change of the fuel injection amount at the time of conventional no load. On the other hand, G2 shows a selected fuel injection amount curve which is a temporal change of the fuel injection amount when the no-load coefficient is selected as the control coefficient of the target value filter 61. In FIG. 6B, L1 shows a conventional actual engine speed curve that is a temporal change in the actual engine speed when there is no load in the related art. On the other hand, L2 represents a selected actual engine speed curve that is a temporal change in the actual engine speed when the no-load coefficient is selected as the control coefficient of the target value filter 61.

<Fuel injection amount>
With respect to the conventional fuel injection amount, as shown in FIG. 6A, the conventional fuel injection amount curve G1 is maximized by greatly overshooting the target fuel injection fee F2 at time U5 immediately after time U4. Once it drops, it overshoots again at time U6, and the fuel injection amount greatly fluctuates. In this case, a large amount of black smoke is discharged to the outside air at time U5 and time U6. On the other hand, the selected fuel injection amount curve G2 when the no-load coefficient is selected as the control coefficient of the target value filter 61 does not cause a turbulence due to overshoot like the conventional fuel injection amount curve G1, and the target value from the early stage. Therefore, there is no problem of discharging a lot of black smoke to the outside air.

<Actual engine speed>
As for the actual engine speed, as shown in FIG. 6 (b), the conventional actual engine speed curve L1 is greatly overshooted by the target speed M6, which is the target value, at time U7, and then temporarily decreased. After that, it overshoots again at time U8, and the actual engine speed greatly fluctuates. On the other hand, the selected actual engine speed curve L2 when the no-load coefficient is selected as the control coefficient of the target value filter 61 takes time to reach the target speed M6, but the conventional actual engine speed curve L1. In this way, the target rotation speed M6 is converged gently without overshooting.

  From the above, not only the control coefficient of the target value filter 61 that realizes good combustion in a loaded state as in the prior art, but also the control coefficient that can realize appropriate combustion even when there is no load (coefficient for no load) ) And selecting the control coefficient according to the presence or absence of a load can prevent a large amount of black smoke from being discharged to the outside air when the fuel injection amount overshoots the target value or more. It becomes possible.

The block diagram which showed schematic structure of the fuel-injection system. The schematic block diagram of a fuel injection pump and its related apparatus. The block diagram which showed the relationship of the information transmission between a throttle instruction value and target rotational speed. The flowchart which showed an example of the process which selects a control coefficient according to the presence or absence of load. The graph which showed an example of the time change of the target engine speed of an engine when either the coefficient for load or the coefficient for no load is selected as a control coefficient of a target value filter. The graph which showed an example which compared the case where the processing of the present invention and the case where the processing of the present invention was performed for the time change of the fuel injection amount at the time of no load and the actual engine speed

DESCRIPTION OF SYMBOLS 1 Fuel injection system 10 Operation part 15 Communication repeater 20 Engine 21 ECM
22 Crankshaft rotation speed sensor 23 Camshaft rotation speed sensor 24 Solenoid valve for retard angle 25 Solenoid valve for advance angle 28 Rack 29 Throttle valve 30 Governor 40 Fuel injection pump

Claims (1)

In a fuel injection system having a control means for performing a filter process when calculating a target engine speed based on a throttle instruction value, a no-load coefficient for performing a filter process corresponding to no load and a load are applied. And a load coefficient for performing a filter process corresponding to the case where there is a load, and the filter process using the no-load coefficient is slower in reaching the target rotational speed than the filter process using the load coefficient. the fuel injection system is set, depending on the presence or absence of the load, characterized in that it comprises a coefficient selecting means for selecting one of the no-load factor or the load factor.

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