JP4448785B2 - Fuel injection system - Google Patents

Description

  The present invention relates to a fuel injection system including a throttle for instructing the engine speed and a spare (emergency) throttle other than the throttle.

  Usually, in a marine engine or the like, the rotational speed (number of revolutions) of the engine is controlled by controlling the rack position of the governor in the fuel injection pump and the intake air amount in the throttle valve. The engine speed is remotely controlled by a throttle which is a lever-type operation tool provided in a cockpit or the like. In recent years, with regard to such engine control, an electronic control governor and an electronic control throttle valve are controlled by a control means such as an engine control unit, and an instruction signal from the throttle is sent to the control means by means of a CAN (Controller Area Network). ) And the like are realized by a communication method.

It is necessary to control the engine speed by such a communication method such as CAN when an abnormality such as an increase in frictional resistance or sticking occurs in the throttle valve and the throttle valve cannot be controlled normally. Patent Document 1 discloses a technique for obtaining a stable engine rotation speed. In other words, the technique disclosed in Patent Document 1 relates to an engine for an outboard motor having a throttle valve. As shown in this document, an outboard motor is used at sea. Therefore, even if an abnormality occurs in the throttle valve, it is necessary to be able to return to the port by itself.On the other hand, it is necessary to perform a shift operation when the ship returns to the port and berths. It is necessary to reduce the rotation speed. For this reason, it is necessary to always ensure control of the engine speed.
JP 2004-92640 A

  By the way, as a state where control of the engine speed is not ensured, there may be a case where a communication abnormality in a communication method such as CAN or an abnormality occurs in the throttle itself as an operation tool. In order to cope with such a case, a spare (emergency) throttle (sub-throttle) connected to a control means such as an engine control unit via a communication path different from the throttle (main throttle) that is normally used. ). That is, when an abnormality occurs in the control of the engine speed by the operation of the main throttle that is normally used by a communication method such as CAN, the engine speed can be controlled by the auxiliary throttle that is a spare throttle. To do.

  When such a configuration is adopted, there is a problem that the engine speed rapidly changes when the throttle for which the engine speed instruction is effective is switched from the main throttle in which the abnormality has occurred to the auxiliary sub-throttle. Conceivable. In other words, since the engine speeds indicated by the throttles are different, if the throttle is switched in a state where the engine speeds indicated by the throttles are greatly different, the engine speeds change abruptly and sudden deceleration or speed increase occurs. Will occur.

  In view of the above, the present invention includes a main throttle that indicates the engine speed and a sub-throttle that indicates the engine speed when an abnormality occurs in the main throttle. To provide a fuel injection system that prevents a sudden change in the engine speed when switching from the main throttle to the sub-throttle, ensures safety, and enables switching of the throttle according to the intention of the operator. Objective.

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

According to a first aspect of the present invention, there is provided a fuel injection system comprising: a main throttle for instructing the engine speed via the control means; and a sub-throttle for instructing the engine speed via the control means instead of the main throttle. When an abnormality occurs in the engine speed instruction by the main throttle, the target speed that is calculated based on the instruction value from the main throttle is gradually reduced to the preset minimum speed. A rotation speed reduction means is provided, and the target rotation speed calculated based on the command value from the sub throttle is increased from the minimum set rotation speed by operating the sub throttle while the target rotation speed is decreasing. The target rotational speed calculated based on the instruction value from the sub-throttle matches the target rotational speed reduced by the target rotational speed reducing means , Those having a throttle switching means for switching the effective throttle from the main throttle to the sub-throttle.

  According to a second aspect of the present invention, the target rotational speed reduction means decreases the target rotational speed at a deceleration that increases every elapse of a preset unit time.

  According to a third aspect of the present invention, the target rotational speed calculated based on the command value from the main throttle is held for a predetermined time from when an abnormality occurs in the engine speed command by the main throttle. A target rotation speed holding means is provided.

  According to a fourth aspect of the present invention, when an abnormality occurs in the engine speed instruction by the main throttle, an alarm for informing the fact and an alarm for informing the start of the target speed reduction by the target speed reduction means are issued. An alarm generating means is provided.

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

  In claim 1, when an abnormality occurs in the main throttle, the actual target rotational speed is gradually decreased regardless of the target rotational speed instructed by the main throttle. Since it is possible to avoid the deceleration and the high-speed state being maintained, it is possible to prevent a shock that is unpleasant for the operator or the like and to ensure safety.

Further, the effective throttle can be switched at the intention of the operator and at the intended timing and the intended engine speed. As a result, when an abnormality occurs in the main throttle, even when the target speed indicated by the main throttle and the target speed indicated by the sub-throttle are significantly different, the engine speed at the time of switching the effective throttle is changed. The change in the number can be reduced, and the behavior of the engine speed can be stabilized, so that safety can be ensured.
Further, it is not necessary to separately provide a device (for example, a changeover switch) for switching the effective throttle, and the effective throttle can be switched using the existing throttle.

  According to the second aspect of the present invention, uncomfortable shock can be prevented and a stable driving feeling can be obtained when the target rotational speed is reduced when an abnormality occurs in the main throttle.

  According to the third aspect of the present invention, since the target rotational speed when the abnormality occurs is maintained for a certain period of time until the target rotational speed is decreased after the abnormality occurs in the main throttle, it is determined that the abnormality has occurred. The engine speed is not suddenly reduced after the driver is notified by a warning or the like at the engine. As a result, the steering state when the abnormality occurs can be maintained within a predetermined time after the abnormality has occurred with respect to the main throttle, and it becomes possible to cope with a decrease in the engine speed in advance. , Can ensure safety.

  In claim 4, when there is an abnormality in the main throttle, an alarm is issued in two stages, when an abnormality occurs in the main throttle and when a decrease in the target rotational speed starts, Therefore, it is possible to ensure the safety of the operation when an abnormality occurs in the main throttle.

  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 40 and related devices, FIG. 3 is a graph showing a change over time in target rotational speed, and FIG. A flowchart showing a series of processing when the throttle is switched, and FIG. 5 is also a time chart.

<Outline configuration>
First, the schematic configuration of the fuel injection system 1 of the present invention will be described with reference to FIG. In addition, although the fuel injection system 1 demonstrated here demonstrates the case where it employ | adopts as a control system of the fuel injection pump of the engine which a ship comprises, for example, the same effect is acquired 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 issue a warning by voice by incorporating a speaker or the like. The main throttle 12 operates, for example, the 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. When 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. 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 move 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.

  In the fuel injection system 1 configured as described above, when the ship is in a normal operation state as described above, the main throttle 12 provided in the operation unit 10 becomes an effective throttle, and the main throttle is operated. The fuel injection amount by controlling the rack position of the rack 28 is controlled to control the rotation speed of the engine 20 (the rotation speed of the crankshaft, hereinafter also referred to as “engine rotation speed”). On the other hand, when the ship cannot be operated normally by operating the main throttle 12, the effective throttle is switched from the main throttle 12 to the sub-throttle 13, and the sub-throttle 13 is operated to rotate the engine 20. The number is controlled.

  The main throttle 12 is connected to the ECM 21 via the communication repeater 15 or the like, and the sub-throttle 13 is directly connected to the ECM 21. For example, communication via CAN (Controller Area Network) is used for the main throttle 12, and analog communication is used for the sub-throttle 13. In this case, the operation signal output from the main throttle 12 is input to the ECM 21 via the CAN, and the operation signal output from the sub-throttle 13 is input to the ECM 21 in an analog manner.

  The ECM 21 has a function as a target rotational speed calculation means for calculating a target rotational speed based on the instruction values from the throttles 12 and 13, and an operation signal input from the throttles 12 and 13 is input. The engine speed is controlled based on the target rotational speed calculated based on the instruction value from either one of the target rotational speeds calculated based on (indicated value). That is, the target rotational speed selected here becomes the actual target rotational speed used for the rotational speed control of the engine 20, and the throttle that outputs the operation signal used for calculating the actual target rotational speed It will be effective throttle at.

  In other words, the fuel injection system 1 according to the present invention provides the main throttle 12 with the main throttle 12 for instructing the rotational speed of the engine 20 via the ECM 21 as the control means, and when the abnormality occurs in the main throttle 12. Instead, an auxiliary throttle 13 for instructing the engine speed of the engine 20 is provided via the ECM 21. When an abnormality occurs in the engine speed instruction by the main throttle 12 functioning as an effective throttle in a normal operation state, the effective throttle Is switched from the main throttle 12 to the sub-throttle 13.

  Then, when an abnormality occurs in the engine speed instruction by the main throttle 12, the ECM 21 gradually increases the target speed calculated based on the instruction value from the main throttle 12 to a preset minimum set speed. descend. Here, the case where an abnormality occurs in the engine speed instruction by the main throttle 12 can be considered as follows. That is, it is a case where some abnormality has occurred in communication between the main throttle 12 and the ECM 21 and a communication error has occurred in a communication method such as CAN. In this case, the operation signal output from the main throttle 12 is not normally input to the ECM 21 and the ECM 21 cannot be recognized. In addition, an error occurs in the main throttle 12 itself. In this case, an error signal is output from the main throttle 12 and input to the ECM 21.

  As described above, when an abnormality occurs in the main throttle 12, the ECM 21 determines that a throttle switching request has occurred, and presets the target rotational speed calculated based on the instruction value from the main throttle 12. Gradually decreases to the minimum set speed. That is, when the ECM 21 determines that an abnormality has occurred in the main throttle 12 and a throttle switching request has occurred, the actual target rotational speed that has been calculated based on the indicated value from the main throttle 12 as an effective throttle until then. Gradually decrease. Here, the minimum set rotational speed is the lowest rotational speed among the target rotational speeds indicated by the main throttle 12 and the sub-throttle 13, that is, the rotational speed when the engine 20 is idling, and is preset by the ECM 21. . That is, the ECM 21 is an example of a target rotational speed reduction unit provided in the fuel injection system 1 according to the present invention.

  Thus, when an abnormality occurs in the main throttle 12, the target rotational speed calculated based on the instruction value from the main throttle 12 is gradually reduced to the preset minimum rotational speed, When the abnormality occurs in the main throttle 12, the actual target rotational speed is gradually decreased regardless of the target rotational speed instructed by the main throttle 12, so that rapid deceleration of the ship or the like is avoided. It is possible to prevent shock that is unpleasant for the operator or the like. Further, for example, even when an abnormality occurs while the target rotational speed instructed by the main throttle 12 is in a high speed range, the high speed state is not maintained, and safety can be ensured. .

  Further, when an abnormality occurs in the main throttle 12, it is preferable that the target rotational speed decrease by the ECM 21 as the target rotational speed reducing means is specifically according to the following mode. In other words, the ECM 21 decreases the target rotational speed at a deceleration that increases every time a preset unit time elapses. As shown in FIG. 3, if the target rotational speed designated by the main throttle 12 before the abnormality occurs in the engine rotational speed instruction by the main throttle 12 is Na, and the target rotational speed starts to decrease from time t1. Then, the target rotational speed Na is reduced to the minimum set rotational speed at a deceleration that increases every time a preset unit time Δt elapses. That is, in the graph shown in FIG. 3 in which the horizontal axis represents time and the vertical axis represents the target rotational speed, the slope represents acceleration, so the negative slope represents deceleration (negative acceleration). The target rotational speed is decreased so that the deceleration increases every time unit time Δt has elapsed from time t1 when the decrease in the number starts. Specifically, during the unit time Δt from the time t1, the target rotational speed is decreased at a certain deceleration α1, and during the next unit time Δt, the target is achieved at a deceleration α2 that is higher than the deceleration α1. Reduce the speed. Similarly, the target rotational speed is gradually decreased while increasing the deceleration to α3, α4,. Here, the rate of increase of the deceleration at every elapse of the unit time Δt is, for example, substantially constant.

  As described above, when an abnormality occurs in the main throttle 12 by gradually reducing the target rotational speed calculated based on the instruction value from the main throttle 12 at a deceleration that increases every unit time Δt. When the target rotational speed is reduced, unpleasant shock can be prevented and a stable driving feeling can be obtained. In addition, the aspect of the reduction | decrease of the target rotational speed shown here is an example, and is not limited to this, For example, you may reduce by substantially constant or fixed deceleration.

  Further, when an abnormality occurs in the main throttle 12, the ECM 21 holds the target rotational speed calculated based on the instruction value from the main throttle 12 for a preset predetermined time. That is, the ECM 21 is a target engine speed holding unit that holds the target engine speed calculated based on the instruction value from the main throttle 12 for a predetermined time set in advance from when the abnormality occurs in the main throttle 12. This is an example, and the predetermined time is preset in the ECM 21.

  Specifically, using the graph shown in FIG. 3, for example, it is assumed that the ship is operating with the target rotational speed indicated by the main throttle 12 being Na and an abnormality has occurred in the main throttle 12 at time t0. . In this case, the ECM 21 determines that the throttle switching request has occurred, and then the target rotational speed Na indicated by the main throttle 12 when an abnormality occurs in the main throttle 12 for a predetermined time Ta set in advance. Hold. Then, the target rotational speed is gradually decreased from Na as described above from time t1 after a predetermined time Ta has elapsed from time t0.

  In this manner, the operation unit 10 indicates that an abnormality has occurred by holding the target rotational speed when the abnormality has occurred for a certain period of time until the target rotational speed is decreased after the abnormality has occurred in the main throttle 12. After being notified to the operator by a warning in the section 11 or the like, the engine speed is not suddenly reduced. Thereby, within a predetermined time after the occurrence of an abnormality in the main throttle 12, it is possible to maintain the steering state when the abnormality occurs and to cope with a decrease in the engine speed in advance. Therefore, safety can be ensured. That is, the engine speed is not reduced while the steering state (for example, at the time of steering, etc.) when an abnormality occurs in the main throttle 12, and the state that can cope with the decrease in the engine speed is operated in advance from that state. Therefore, safe driving operation is possible.

  Hereinafter, a series of processes when the effective throttle is switched from the main throttle 12 to the sub-throttle 13 will be described with reference to a flowchart shown in FIG. 4 and a time chart shown in FIG. 5 in addition to FIG. In the normal operation state of the ship, the engine speed is instructed by the main throttle 12 via the ECM 21. That is, in this state, the main throttle 12 is an effective throttle, and when the operator operates the main throttle 12, the ECM 21 detects an operation signal from the main throttle 12 and sets the indicated value from the main throttle 12. Based on this, the target rotational speed is calculated (S100). In this state, the target rotational speed calculated based on the instruction value from the main throttle 12 is the actual target rotational speed used for the rotational speed control of the engine 20.

  Then, the ECM 21 determines whether or not an abnormality has occurred in the engine speed instruction from the main throttle 12 (S110). If it is determined that an abnormality has occurred in the engine speed instruction from the main throttle 12, the process proceeds to step S120. On the other hand, if it is not determined that an abnormality has occurred in the engine speed instruction from the main throttle 12, the process proceeds to step S100. That is, as long as there is no abnormality with respect to the main throttle 12, the ECM 21 continues the normal operation state.

  If it is determined in step S110 that an abnormality has occurred in the main throttle 12 at time t0, the ECM 21 issues an alarm notifying the display unit 11 of the operation unit 10 that an abnormality has occurred in the main throttle 12 ( S120). Then, from the time t0 when the abnormality occurs in the main throttle 12, as described above, the target rotational speed Na instructed by the main throttle 12 when the abnormality occurs is held for a predetermined time Ta, and then at the time t1. The target rotational speed starts decreasing (S130). That is, the ECM 21 holds the target rotational speed Na when an abnormality occurs in the main throttle 12 for a predetermined time Ta from the time t0 to the time t1, and then starts the target rotational speed from the time t1. It gradually decreases to the set rotational speed No. At this time, the ECM 21 starts a decrease in the target rotation speed as the target rotation speed reduction means, and issues a warning notifying the start of the decrease in the target rotation speed (S130). That is, the ECM 21 is an example of an alarm generating unit that issues an alarm for notifying that when an abnormality has occurred in the engine speed instruction by the main throttle 12 and an alarm for notifying the start of a decrease in the target speed. A method for performing these alarms is not limited to displaying such a warning, but may be a warning by buzzer or sound, a warning by lighting a lamp, or a combination thereof. For example, an abnormality has occurred in the main throttle 12. At that time, an alarm is issued by turning on or blinking the lamp.After that, when the target speed starts to decrease, the lamp that is lit is blinked or the period of the blinking lamp is changed. It is conceivable that a notification is made by making a notification.

  In this way, when there is an abnormality in the main throttle 12, an alarm is issued in two stages when an abnormality occurs in the main throttle 12 and when a decrease in the target rotational speed starts, so that the operator can Since it is possible to take appropriate measures, it is possible to ensure the safety of the operation when the abnormality occurs in the main throttle 12.

  In step S130, after the target rotational speed designated by the main throttle 12 starts to decrease, the ECM 21 determines that the target rotational speed calculated based on the designated value from the sub-throttle 13 is the minimum set rotational speed. It is determined whether the number is No (S140). Here, when it is determined that the target rotational speed instructed by the sub-throttle 13 is the minimum set rotational speed No, when an abnormality occurs in the main throttle 12, the target rotational speed already instructed by the sub-throttle 13 Is the minimum set speed No. and the target speed indicated by the sub-throttle 13 is set to the minimum set speed No by the operation of the sub-throttle 13 by the operator after an abnormality has occurred in the main throttle 12. There is.

  That is, when an abnormality has occurred in the main throttle 12, if the target rotational speed indicated by the sub-throttle 13 is already the minimum set rotational speed No, the process automatically proceeds to step S150 via step S140. If the target rotational speed designated by the sub-throttle 13 is not the minimum set rotational speed No, the process proceeds to step S150 by the operation of the sub-throttle 13 by the operator. The latter case will be described with reference to FIG. 5. It is assumed that the target rotational speed indicated by the sub-throttle 13 when an abnormality occurs in the main throttle 12 is Nb. An abnormality occurs in the main throttle 12, and a decrease in the target rotational speed designated by the main throttle 12 is started from time t1, and the sub-throttle 13 is operated by the operator while the target rotational speed is decreasing. As a result, the target rotational speed Nb instructed by the sub-throttle 13 is reduced (see point A). If the operation of the sub-throttle 13 is to set the target speed indicated by the sub-throttle 13 to the minimum set speed No, the target speed Nb indicated by the sub-throttle 13 is the minimum set speed. No is reached (see point B).

  In this way, if it is determined that the target rotational speed indicated by the sub-throttle 13 has reached the minimum set rotational speed No in any case, the ECM 21 has generated the right to switch to the effective throttle for the sub-throttle 13. The process proceeds to step S150.

  As described above, the ECM 21 determines whether or not the target speed indicated by the sub-throttle 13 has increased from the minimum set speed No from the state where the target speed indicated by the sub-throttle 13 is at the minimum set speed No. Is determined (S150). That is, here, it is determined whether or not the operator has performed an operation for increasing the target rotational speed indicated by the sub-throttle 13 from the minimum set rotational speed No. As a result, the driver's intention to switch the effective throttle to the sub throttle 13 is involved. In step S150, when the sub-throttle 13 is operated by the operator and it is determined that the target speed indicated by the sub-throttle 13 has increased from the minimum set speed No, the process proceeds to step S160.

  When the target rotation speed indicated by the sub-throttle 13 starts to increase from the minimum set rotation speed No by the operation of the sub-throttle 13 by the operator (see point C in FIG. 5), the ECM 21 performs the target rotation indicated by the sub-throttle 13 It is determined whether or not the number matches the actual target rotational speed that gradually decreases as a result of an abnormality occurring in the main throttle 12 as described above (S160). If it is determined that the target rotational speed indicated by the sub-throttle 13 matches the actual target rotational speed that is decreasing, the ECM 21 determines that the target rotational speed indicated by the sub-throttle 13 and the actual target rotational speed that is decreasing. When the number matches (see intersection D in FIG. 5), the effective throttle is switched to the sub-throttle 13 (S170). That is, in a state where the sub-throttle 13 is an effective throttle, the ECM 21 detects an operation signal from the sub-throttle 13 when the sub-throttle 13 is operated by the operator, and the instruction value from the sub-throttle 13 is set. Based on this, the target rotational speed is calculated. In this state, the target rotational speed calculated based on the instruction value from the sub-throttle 13 becomes the actual target rotational speed. That is, when the target rotational speed calculated based on the instruction value from the sub-throttle 13 is increased from the minimum set rotational speed No while the actual target rotational speed Na is decreasing, the ECM 21 instructs This is an example of throttle switching means for switching the effective throttle from the main throttle 12 to the sub-throttle 13 when the target rotational speed calculated based on the value matches the actual target rotational speed at which the ECM 21 decreases.

  As described above, when the effective throttle is switched to the sub-throttle 13, the target rotational speed instructed by the sub-throttle 13 is increased from the minimum set rotational speed No in order to involve the operator's intention. Another reason is to ensure that the effective throttle is switched to the sub-throttle 13. That is, by increasing the target rotational speed instructed by the sub-throttle 13 from the minimum set rotational speed No, for example, when an abnormality occurs in the main throttle 12, the target rotational speed instructed by the main throttle 12 is Even in the case of the minimum set rotational speed No, a state in which the target rotational speed instructed by the sub-throttle 13 and the actual target rotational speed being decreased as a condition for switching the effective throttle to the sub-throttle 13 ( Since the intersection D) in FIG. 5 can be generated reliably, the effective throttle is reliably switched to the sub-throttle 13.

  In the series of processes when the effective throttle is switched to the sub-throttle 13 as described above, the actual target rotational speed instruction used for controlling the rotational speed of the engine 20 changes as follows. That is, as shown in FIG. 5, the target rotational speed instructed by the main throttle 12 is the actual target rotational speed until the time t0 when the abnormality occurs in the main throttle 12, and from the time t0 through the time t1. The target rotational speed that is gradually decreased becomes the actual target rotational speed. Then, from the time (time t2) when the effective throttle is switched from the main throttle 12 to the sub-throttle 13 while the actual target speed is decreasing, the target speed indicated by the sub-throttle 13 is the actual target rotation. Number. During the process from time t0 when the abnormality occurs in the main throttle 12 to time t2 when the effective throttle is switched to the sub-throttle 13, for example, communication between the main throttle 12 and the ECM 21 is recovered for some reason. When the engine speed instruction by the main throttle 12 returns to the normal state, the ECM 21 continues normal operation with the main throttle 12 as an effective throttle, assuming that the throttle switching request has been canceled.

  By switching the effective throttle from the main throttle 12 to the sub-throttle 13 through the processing as described above, the effective throttle can be switched at the intention of the operator and at the intended timing and the intended engine speed. . That is, the operator operates the sub-throttle 13 (specifically, sets the target speed indicated by the sub-throttle 13 to the minimum after an abnormality occurs in the main throttle 12 and the actual target rotational speed starts to decrease). The sub-throttle 13 can be switched to the effective throttle at the intended target rotational speed at the intended timing by arbitrarily performing the timing of increasing from the set rotational speed No or how to increase the rotational speed. As a result, when an abnormality occurs in the main throttle 12, even when the target rotational speed designated by the main throttle 12 and the target rotational speed designated by the sub-throttle 13 are greatly different, the effective throttle is switched. Therefore, it is possible to reduce the change in the engine speed in the engine and to stabilize the behavior of the engine speed, so that safety can be ensured. Further, it is not necessary to separately provide a device (for example, a changeover switch) for switching the effective throttle, and the effective throttle can be switched using the existing throttle.

The block diagram which showed schematic structure of the fuel-injection system. The schematic block diagram of the fuel-injection pump 40 and its related apparatus. The graph which shows the time change of target rotation speed. The flowchart which shows a series of processes when an effective throttle switches. Similarly time chart.

DESCRIPTION OF SYMBOLS 1 Fuel injection system 10 Operation part 11 Display part 12 Main throttle 13 Sub throttle 20 Engine 21 ECM

Claims (4)

A fuel injection system comprising: a main throttle for instructing the engine speed via a control means; and a sub-throttle for instructing the engine speed via the control means instead of the main throttle, wherein the main throttle When there is an abnormality in the engine speed instruction by the engine, there is provided a target speed reduction means for gradually reducing the target speed calculated based on the instruction value from the main throttle to a preset minimum speed. When the target speed calculated based on the instruction value from the sub-throttle is increased from the minimum set speed by operating the sub-throttle while the target speed is decreasing, When the target rotational speed calculated based on the indicated value matches the target rotational speed reduced by the target rotational speed reducing means, the effective throttle is The fuel injection system characterized by comprising a throttle switching means for switching the sub-throttle from serial main throttle.   2. The fuel injection system according to claim 1, wherein the target rotational speed reduction means reduces the target rotational speed at a deceleration that increases every elapse of a preset unit time. A target speed holding means for holding a target speed calculated based on an instruction value from the main throttle for a predetermined time after an abnormality occurs in the engine speed instruction by the main throttle; The fuel injection system according to claim 1, further comprising: When an abnormality occurs in the engine speed instruction by the main throttle, an alarm generation means for issuing an alarm for notifying that effect and an alarm for informing the start of a decrease in the target speed by the target speed reduction means is provided. The fuel injection system according to claim 3 .

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