JP4557760B2 - Fuel injection system - Google Patents

Description

  The present invention relates to a fuel injection system that automatically calibrates a rack position under no load, which is one of engine control standards.

  A conventional diesel engine is operated with a certain phase difference between a phase of a camshaft that determines a fuel injection timing and a phase of a crankshaft of the engine, which is a driving source of fuel injection in a fuel injection pump. By changing the phase difference so as to be on the advance side or retard side according to the state of the engine, the fuel injection timing is changed, and the engine can be operated efficiently. As a device for changing the phase of the camshaft of the fuel injection pump, a hydraulic timer unit is known. In the hydraulic timer unit, the phase angle of both shafts is changed between a camshaft coupling fixed to the camshaft of the fuel injection pump and a pump drive gear to which the rotation of the crankshaft is transmitted. Timer pistons (which may also be referred to as “shuttle pistons”) are provided. These are provided with a timer piston so as to be fitted in a straight spline on the outer peripheral surface of the camshaft coupling, and further provided with a pump drive gear so as to be helically spline fitted into the outer peripheral surface of the timer piston. . With this configuration, the phase difference between the camshaft coupling and the pump drive gear can be changed by sliding the timer piston in the spline direction of the camshaft coupling. The timer piston is slid by hydraulic pressure, and the hydraulic pressure is controlled by an ECM that controls the engine. Therefore, the fuel injection timing can be made appropriate by the ECM controlling the timer piston to the advance side or the retard side according to the state of the engine.

Incidentally, the target phase difference, which is one of the ECM command values, is determined based on the load factor. This load factor is determined by the relationship between the rack position at a certain engine speed, the rack position at maximum injection, and the rack position at no load. This relationship will be described with reference to FIG. In FIG. 3, for example, in a state where a certain load is applied, the actual rack position, which is the actual rack position when the engine speed is M1, is R1 (point E1). Further, the rack position at the time of no load is referred to as “no load rack position”, and this no load rack position is obtained in advance for each engine speed and stored in the ECM as a no load rack position curve RS. For example, the no-load rack position at the engine speed M1 is obtained as R2. On the other hand, the rack position at which the maximum amount of fuel is injected is referred to as “maximum rack position”, and this maximum rack position is determined in advance for each engine speed and stored in the ECM as a maximum rack position curve RM. For example, the maximum rack position at the engine speed M1 is obtained as R3. The maximum rack position is determined by the specifications and characteristics of the engine, the fuel injection pump, etc., and the rack position does not become a larger value (increase side) than the maximum rack position. That is, the maximum rack position curve RM indicates the upper limit line of the rack position. In FIG. 3, for example, the load factor at the point E1 is calculated as follows.
Load factor = (actual rack position R1−unloaded rack position R2) ÷ (maximum rack position R3−unloaded rack position R2)
That is, the load factor is defined by the ratio of “the difference from the actual rack position to the no-load rack position” and “the difference from the maximum rack position to the no-load rack position”. Therefore, the ECM calculates a load factor from the above-described relationship, and performs a process of determining a target phase difference by extracting a phase difference corresponding to the calculated load factor from a map or the like that is stored in advance.
JP 2004-218636 A

  However, the no-load rack position curve RS described above is stored in advance in the ECM or the like, but the locus of the actual no-load rack position, which is the actual rack position at the time of no load, often does not match and is different. It is generally known. For this reason, even if the load factor is calculated according to the above relationship, it is not possible to obtain a load factor that matches the actual engine state. Therefore, the fuel injection timing determined by this load factor also matches the actual engine state. Is not. Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to improve the control accuracy by matching the trajectory of the actual no-load rack position and the no-load rack position curve RS. A fuel injection system is provided.

  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 rack for adjusting a fuel injection amount of a fuel injection pump, and storing a rack position at the time of no load as a no-load rack position curve in advance. An adjustment amount calculation means for calculating an adjustment amount that is a difference between an actual rack position in the number and a rack position on the no-load rack position curve corresponding to the engine speed, and the adjustment amount calculation means Adjustment amount storage means for storing the adjustment amount, and when the predetermined engine speed at no load increases from the minimum speed, the amount of change in the rack position with respect to the increase in the speed gradually decreases. a rotational speed to begin, the adjustment amount calculating means, which receives the calibration processing request, and set to a predetermined engine speed during the no-load, and calculates the adjustment amount A.

  According to a second aspect of the present invention, the adjustment amount calculation means calculates one adjustment amount.

  According to a third aspect of the present invention, the adjustment amount calculation means calculates a plurality of the adjustment amounts.

  According to a fourth aspect of the present invention, a calibration unloaded rack position curve, which is a transition of the unloaded rack position curve based on the adjustment amount, is mapped and stored.

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

According to a first aspect of the present invention, there is provided a fuel injection system including a rack for adjusting a fuel injection amount of a fuel injection pump, and storing a rack position at the time of no load as a no-load rack position curve in advance. An adjustment amount calculating means for calculating an adjustment amount that is a difference between an actual rack position at the engine speed and a rack position on the no-load rack position curve corresponding to the engine speed, and the adjustment amount calculating means An adjustment amount storage means for storing the adjusted amount of adjustment, and the predetermined engine speed at no load is a change amount of the rack position with respect to the increase amount of the rotation speed when increasing from the minimum rotation speed. there a number of revolutions to begin gradually decreasing, the adjustment amount calculation means receives the calibration processing request, and set to a predetermined engine speed during the no-load, to calculate the adjustment amount It is possible to calculate an appropriate no-load rack position corresponding to the engine speed based on a curve that has been shifted by an adjustment amount to a pre-stored no-load rack position curve, which is more consistent with the actual machine than before. Therefore, it is possible to accurately calculate the load factor and improve the control performance of the engine.
In addition, even if there are variations due to assembly errors between the assembled products of the fuel injection pump and the hydraulic timer unit, it is possible to calculate a load factor that is consistent with the actual machine. The engine control performance can be improved, and the control performance can be made uniform.

  With the configuration of the second aspect, the adjustment amount can be easily calculated with a simple algorithm.

  According to the configuration of claim 3, when the unloaded rack position curve stored in advance is changed based on the adjustment amount so as to coincide with the locus of the actual no-load rack position, the case where a plurality of adjustment amounts are used is one. It becomes possible to match with higher precision than in the case.

  According to the configuration of the fourth aspect, since the calibration unloaded rack position curve is mapped and stored, the unloaded rack position corresponding to the actual engine speed can be extracted at a high speed, and the load with better accuracy than before can be obtained. The rate can be calculated at high speed.

  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 is not intended to 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 graph and a diagram showing a relationship between engine speed and rack position. 4 is a flowchart showing a series of calibration processes for calculating the adjustment amount G and calibrating the no-load rack position curve, and FIG. 5 shows an example when the no-load rack position curve is transitioned in the calibration process. Graph.

<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, the timer piston 52 is indicated by a one-dot chain line for the sake of convenience in the state of being divided into two vertically, the state moved to the retard side position is indicated by the timer piston 52a, and the state moved to the advance side position Is indicated by a 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 addition, as already explained with reference to FIG. 3, the load factor is defined by the ratio of “difference from actual rack position to no-load rack position” and “difference from maximum rack position to no-load rack position”. It is what is done. The no-load rack position for calculating the load factor is calculated from the no-load rack position curve RS stored in advance in the ECM 21, but the actual no-load rack position, which is the actual rack position at the time of no load, is calculated. Does not match the trajectory. A calibration process for matching the no-load rack position curve RS to the actual no-load rack position will be described with reference to the flowchart shown in FIG. An example of changes in the no-load rack position curve RS, the maximum rack position curve RM, the engine speed, and the like in this calibration process will be described with reference to FIG.

  First, the ECM 21 receives a calibration processing request (S10). The reception of the calibration processing request in step S10 is performed by inputting the calibration processing request to the ECM 21 by a device such as a dedicated maintenance checker. Then, the ECM 21 determines whether or not the clutch is in the engaged state by detecting with a clutch detection sensor or the like (S12). When it is determined in the above step S12 that the clutch is in the engaged state, the normal mode for performing the normal control is entered, so the process proceeds to step S24, and on the other hand, the clutch is determined not to be in the engaged state. Is in the calibration mode for performing the calibration process, the process proceeds to step S14. When the process proceeds to step S14, the ECM 21 sets the rotational speed of the engine 20 to a predetermined calibration rotational speed (S14). In the following, an example of the rotation speed for calibration will be described as an engine speed M2 as shown in FIG.

  The ECM 21 detects the actual no-load rack position (that is, the actual no-load rack position) based on the output value of the position detection sensor of the rack 28 (S16). That is, since the engine 20 is in a no-load state (clutch disengaged state), the actual rack position measured in step S16 is the actual no-load rack position. The actual no-load rack position measured in step S16 will be described as R6 (point E6) in FIG. 5, for example, and the actual no-load rack position locus will be described as an actual no-load rack position locus RR1.

<Water temperature correction amount>
By the way, it is known that the rack position under no load changes due to the influence of the temperature of the entire apparatus (for example, cooling water temperature). Therefore, the ECM 21 stores a no-load rack position curve RS at a reference temperature obtained in advance at the development stage or the like, and calculates the load factor by transitioning the no-load rack position curve RS according to the cooling water temperature. Was. For example, when the no-load rack position curve RS is determined with a reference temperature of 50 degrees, and the cooling water temperature when the engine 20 is actually operated with no load is 80 degrees, the ECM 21 is The load factor is calculated by using the transition of the no-load rack position curve RS by the temperature difference of 30 degrees (no-load rack position curve RS1). That is, it can be said that the no-load rack position curve RS1 is obtained by correcting the no-load rack position curve RS according to the cooling water temperature. Therefore, hereinafter, the difference (that is, R5-R4) between the no-load rack position curve RS1 (point E5) and the no-load rack position curve RS (point E4) at the engine speed M2 is referred to as a water temperature correction amount F. The water temperature correction amount F is stored in the ECM 21 in association with the temperature difference from the reference temperature (50 degrees), for example, and the ECM 21 detects the cooling water temperature to thereby calculate the water temperature correction amount F. Can be determined.

<Adjustment amount>
The ECM 21 uses the difference (that is, R6-R5) between the actual no-load rack position R6 (point E6) measured in step S16 and the no-load rack position curve RS1 (point E5) at the engine speed M2 as the adjustment amount G. One is calculated (S18). That is, the ECM 21 calculates an adjustment amount that calculates an adjustment amount that is a difference between an actual rack position at a predetermined engine speed at no load and a rack position on the no-load rack position curve corresponding to the engine speed. It also functions as a means. Then, the ECM 21 stores the adjustment amount G calculated in step S18 (S20). That is, the ECM 21 also functions as an adjustment amount storage unit for storing the adjustment amount G.

  The adjustment amount G calculated in step S18 is the difference between the actual no-load rack position locus RR1 and the no-load rack position curve RS1. In other words, the transition of the no-load rack position curve RS1 by the adjustment amount G coincides with the actual no-load rack position locus RR1. Therefore, the ECM 21 calculates and stores the transition of the no-load rack position curve RS1 by the adjustment amount G as the calibration no-load rack position curve RS2 (S22). Then, the ECM 21 ends the calibration mode for making the no-load rack position curve RS coincide with the actual no-load rack position, and shifts to the normal mode in which normal control is performed (S24). By performing such processing, the ECM 21 can calculate the no-load rack position corresponding to the engine speed based on the calibration no-load rack position curve RS2 in the normal control. It becomes possible to calculate the load factor consistent with the actual machine with high accuracy, and to improve the control performance of the engine. Further, by mapping the calibration no-load rack position curve RS2 and storing it in the ECM 21, it becomes possible for the ECM 21 to extract the no-load rack position corresponding to the actual engine speed at high speed. It becomes possible to calculate a load factor with good accuracy at high speed.

<Multiple adjustment amounts>
In the process of step S18 described above, the ECM 21 calculates only one adjustment amount G at the engine speed M2, but a plurality of adjustment amounts G can also be calculated. For example, in the first calibration process, the ECM 21 performs the processing from step S16 to step S20 using the engine speed M2 as the calibration speed, and then sets the calibration speed to a speed other than the engine speed M2. Then, the process from step S16 to step S20 is performed. That is, by shifting the process to step S14 a plurality of times in a loop as shown by a dotted line in FIG. 4 and setting a different calibration rotation speed each time, the actual no-load rack position locus RR1 and no-load shown in FIG. The adjustment amount, which is the difference from the rack position curve RS1, can be sampled at a plurality of locations in the horizontal axis direction (engine speed axis direction). Therefore, when the no-load rack position curve RS1 is transitioned based on the adjustment amount so as to coincide with the actual no-load rack position locus RR1, the case where a plurality of adjustment amounts are used is more accurate than the case where one is used. It is possible to match. Therefore, it is desirable to calculate only one adjustment amount when it is desired to simplify the algorithm, and to calculate a plurality of adjustment amounts when it is desired to transition the no-load rack position curve RS1 with high accuracy.

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. A graph showing the relationship between engine speed and rack position. The flowchart which showed a series of calibration processes for calculating the adjustment amount G and calibrating a no-load rack position curve. The graph which showed an example when changing a no-load rack position curve by calibration processing.

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 (4)

An actual rack position at a predetermined engine speed at no load in a fuel injection system having a rack for adjusting a fuel injection amount of a fuel injection pump and storing a rack position at no load as a no-load rack position curve in advance And an adjustment amount calculation means for calculating an adjustment amount that is a difference between the rack position on the unloaded rack position curve corresponding to the engine speed, and an adjustment for storing the adjustment amount calculated by the adjustment amount calculation means The predetermined engine speed at the time of no load is a rotational speed at which the amount of change in the rack position with respect to the increase in the rotational speed begins to gradually decrease when the rotational speed increases from the minimum rotational speed. Te, the adjusting amount calculating unit receives the calibration processing request, and set to a predetermined engine speed during the no-load, fuel injection and calculates the adjustment amount Stem.   The fuel injection system according to claim 1, wherein the adjustment amount calculation means calculates one adjustment amount.   The fuel injection system according to claim 1, wherein the adjustment amount calculation means calculates a plurality of the adjustment amounts.   The fuel injection system according to any one of claims 1 to 3, wherein a calibration unloaded rack position curve, which is a transition of the unloaded rack position curve based on the adjustment amount, is stored as a map. .

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