JP2014202075A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device capable of acquiring a phase difference of a crank angle between pressure feed timing and fuel injection timing without performing positioning in attachment of a fuel pump and an internal combustion engine.SOLUTION: The fuel injection device includes a common rail 12 for storing fuel in a high pressure state, a fuel pump 11 connected to a crankshaft 41 of an engine to be driven and pressure feeding the fuel to the common rail 12, a fuel injection valve 20 for injecting the fuel stored in the common rail 12, a fuel pressure sensor 13 for detecting a fuel pressure of the common rail 12 for each of prescribed periods, gradient calculating means 30 for calculating an ascent gradient of the fuel pressure accompanied by pressure feeding by the fuel pump 11 on the basis of the fuel pressure detected for each of the prescribed periods, timing estimating means 30 for estimating the pressure feed timing by the fuel pump 11 on the basis of the calculated ascent gradient, and storage means 34 for storing a rotation angle difference of the crankshaft 41 between the estimated pressure feed timing and the injection timing by the fuel injection valve 20.

Description

  The present invention relates to a fuel injection device that stores fuel pressure-fed from a fuel pump in a high-pressure state in an animal pressure vessel and supplies the stored high-pressure fuel by a fuel injection valve.

  A fuel pump that is driven by the rotational force of the crankshaft of the internal combustion engine to increase the pressure of the fuel pumped up from the fuel tank and pump it, a stock pressure vessel that stores the fuel pumped from the fuel pump in a high pressure state, and a stock pressure vessel There is known a fuel injection device that includes a fuel injection valve that injects the high-pressure fuel that has been injected (for example, Patent Document 1).

  In such a fuel injection device, in order to improve the injection amount accuracy and suppress the overshoot of the fuel pressure, the pumping timing from the fuel pump to the animal pressure vessel and the fuel injection timing, that is, the crank angle at the top dead center of the internal combustion engine. The phase difference is fixed.

JP 2003-278620 A

  In the fuel injection device as described above, the relative position between the key of the pump shaft and the gear on the internal combustion engine side is fixed, so that the phase difference between the crank angle between the pumping timing and the fuel injection timing is fixed. Therefore, when assembling the internal combustion engine in the vehicle, it is necessary to rotate the fuel pump or the internal combustion engine so that the key position of the pump shaft matches the predetermined position of the gear on the internal combustion engine side. There is a problem that it takes time and effort.

  However, unless the key position of the pump shaft and the predetermined position of the gear on the internal combustion engine are aligned, the phase difference between the crank angles at the pumping timing and the fuel injection timing cannot be acquired. As a result, it is also impossible to perform various corrections using the crank angle phase difference to suppress variations in the injection amount and overshoot of the fuel pressure.

  In view of the above circumstances, the present invention provides a fuel injection device capable of acquiring a crank angle phase difference between a pumping timing and a fuel injection timing without performing alignment when the fuel pump and the internal combustion engine are assembled. The main purpose.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a fuel injection device, and is a livestock pressure vessel that stores fuel in a high-pressure state, and is driven by being connected to a crankshaft of an internal combustion engine. A fuel pump that pumps the fuel against the fuel, a fuel injection valve that injects the fuel stored in the animal pressure vessel, a fuel pressure detecting means that detects a fuel pressure in the animal pressure vessel every predetermined period, and the fuel pressure Based on the fuel pressure detected every predetermined period by the detecting means, an inclination calculating means for calculating an increase inclination of the fuel pressure accompanying the pumping by the fuel pump, and an increase inclination of the fuel pressure calculated by the inclination calculating means. Timing estimation means for estimating the timing of pumping by the fuel pump; timing of pumping estimated by the timing estimating means; and timing of injection by the fuel injection valve And a storage means for storing the rotation angle difference of the crankshaft in.

  According to the first aspect of the present invention, the fuel is pumped to the animal pressure vessel by the fuel pump driven by the power of the internal combustion engine. The pumped fuel is stored in the animal pressure vessel in a high pressure state. The fuel stored in the animal pressure vessel is injected by the fuel injection valve.

  The fuel pressure in the stock pressure vessel is detected every predetermined period, and the rising slope of the fuel pressure accompanying pumping is calculated based on the detected fuel pressure. Then, the pumping timing is estimated based on the calculated fuel pressure rising slope, and the crankshaft rotation angle difference between the estimated pumping timing and the injection timing is stored.

  Therefore, the phase difference of the crank angle between the pumping timing and the injection timing can be estimated by estimating the pumping timing by the fuel pump without previously aligning the key of the pump shaft and the predetermined tooth of the internal combustion engine side gear. Can be obtained.

The figure which shows the outline of a fuel-injection apparatus. Sectional drawing which shows the structure of a fuel pump. The figure which shows the fuel pressure detected for every predetermined period at the time of pumping. The flowchart which shows the process sequence which estimates a pumping start timing.

  Hereinafter, an embodiment in which a fuel injection device is mounted on a vehicle will be described with reference to the drawings. The fuel injection device according to the present embodiment is assumed to be mounted on a four-cylinder diesel engine.

  With reference to FIG. 1, the outline of the fuel-injection apparatus which concerns on this embodiment is demonstrated. This fuel injection device includes a fuel tank 10, a fuel pump 11, a common rail 12 (stock pressure vessel), a fuel pressure sensor 13 (fuel pressure detection means), and fuel injection valves 20 (# 1, # 2, # 3 provided in each cylinder). , # 4) and ECU 30.

  The fuel tank 10 is a tank (container) for storing fuel (light oil) of the target engine.

  The fuel pressure pump 11 is configured as shown in FIG. The fuel pump 11 includes a low pressure pump 40 and a high pressure pump 50. The fuel pump 11 is configured to pressurize the fuel pumped up from the fuel tank 10 through the fuel filter 10a by the low-pressure pump 40 by the high-pressure pump 50 and discharge (pressure-feed) it to the common rail 12 through the pipe 11e. Has been.

  Of the two types of pumps constituting the fuel pump 11, the low-pressure pump 40 is configured as a trochoid feed pump. An outer rotor is provided on the outer side, and an inner rotor is provided on the inner side. The space created by each rotor is increased or decreased according to the rotation of each rotor, and fuel is sucked and discharged in accordance with the increase or decrease. The low pressure pump 40 sucks the fuel in the fuel tank 10 from the inlet 42 and sends it to the high pressure pump 50, and is driven by the rotation of the drive shaft 41. The drive shaft 41 is interlocked with the crankshaft 24 (FIG. 1), and is driven by power from the engine output. That is, the drive shaft 41 is driven as the crankshaft 24 rotates, and rotates at a ratio of “1/1” or “1/2” to one rotation of the crankshaft 24, for example.

  The fuel sucked up by the low-pressure pump 40 passes through the fuel filter 42a and is sent to a suction adjustment valve 60 (SCV: Suction Control Valve). At this time, the discharge pressure (fuel pressure) of the low-pressure pump 40 is limited (adjusted) to a predetermined pressure or less by the regulator valve 43. The regulator valve 43 communicates the discharge side and the supply side of the low-pressure pump 40 when the discharge pressure of the low-pressure pump 40 is equal to or higher than a predetermined pressure. Further, the temperature of the fuel sent to the intake adjustment valve 60 is detected by the fuel temperature sensor 43a.

  The suction regulating valve 60 (regulating valve) is configured to include, for example, a normally-on type linear solenoid solenoid valve that opens when not energized. The suction fuel amount of the high-pressure pump 50 and, consequently, the pressure feed from the high-pressure pump 50 to the common rail 12 This adjusts the amount of pumping. The amount of fuel drawn from the low pressure pump 40 to the high pressure pump 50 through the fuel passage 44 can be adjusted by controlling the energization time (drive current amount), that is, the valve opening period, for the intake adjustment valve 60 by a control signal from the ECU 30. It has become. That is, the fuel sent by the low-pressure pump 40 is adjusted to a required discharge amount (target fuel pumping amount) by the suction adjusting valve 60 and enters the high-pressure pump 50 through the suction valve 53 (suction valve).

  The high-pressure pump 50 is a plunger pump that pressurizes the fuel metered by the suction adjustment valve 60 and discharges the fuel to the common rail 12. The high-pressure pump 50 is roughly configured to include a plunger 51 that is reciprocally driven by a drive shaft 41, and a pressurizing chamber 52a formed between the inner wall 52b of the housing 52 and the top surface of the plunger 51. The volume (volume) of the pressure chamber 52a (plunger chamber) changes due to the reciprocation of the plunger 51 in the axial direction.

  The plunger 51 is pressed against a ring cam 56 mounted around an eccentric cam 55 (eccentric cam) by a spring 57. Although not shown, in detail, a cylindrical shaft hole for assembling the drive shaft 41 is formed at the center of the ring cam 56 having a substantially rectangular parallelepiped shape. A cylindrical eccentric cam 55 corresponding to the shape of the shaft hole is attached to the drive shaft 41 so as to be eccentric. Then, the ring cam 56 is assembled on the eccentric cam 55 of the drive shaft 41 in such a manner that the drive shaft 41 passes through the shaft hole of the eccentric cam 55, so that the drive shaft 41 and the ring cam 56 are connected to the eccentric cam 55. It is connected through. In the high-pressure pump 50, when the drive shaft 41 rotates, the eccentric cam 55 rotates eccentrically, and the ring cam 56 follows and displaces it, thereby pushing (or pulling) the plunger 51 in the axial direction. In this way, in the present embodiment, the two plungers 51 reciprocate between the pressure top dead center and the pressure bottom dead center. The number of plungers 51 is not limited to two.

  On the suction side of the high-pressure pump 50, a suction valve 53 that connects or blocks the pressurizing chamber 52a and the low-pressure pump 40 is disposed. On the other hand, the discharge side of the high-pressure pump 50 is similarly provided with a discharge valve 54 for communicating or blocking the pressurizing chamber 52a and the common rail 12 side. That is, when the volume of the pressurizing chamber 52a increases with the lowering of the plunger 51 and the pressure in the pressurizing chamber 52a decreases, the discharge valve 54 closes and the suction valve 53 opens. As a result, fuel is supplied from the low pressure pump 40 into the pressurizing chamber 52 a via the suction adjusting valve 60. Conversely, when the volume of the pressurizing chamber 52a decreases as the plunger 51 rises and the pressure in the pressurizing chamber 52a increases, the suction valve 53 is now closed. When the pressure in the pressurizing chamber 52a reaches a predetermined pressure, the discharge valve 54 is opened, and the high-pressure fuel pressurized in the pressurizing chamber 52a is supplied toward the common rail 12. The fuel pump 11 supplies the fuel by pressure in this way.

  Returning to FIG. 1, the common rail 12 stores the fuel pumped by the fuel pump 11 through the pipe 11e in a high pressure state. That is, the common rail 12 is a kind of surge tank that holds high-pressure fuel under stock pressure. The fuel pressure in the common rail 12 becomes a supply pressure when fuel is injected from the fuel injection valve 20. When the supply pressure is changed and fuel is injected from the fuel injection valve 20 for the same period, the injection amount increases as the supply pressure increases.

  A fuel pressure sensor 13 (fuel pressure detecting means) provided on the common rail 12 detects the fuel pressure in the common rail 12 every predetermined period (for example, 30 ° CA) (see FIG. 3). The predetermined period is a period shorter than the driving cycle of the plunger 51, and may be either a predetermined time or a predetermined crank angle. That is, the fuel pressure sensor 13 detects the fuel pressure in the common rail 12 at a predetermined time interval or a predetermined crank angle interval.

  The fuel stored in the common rail 12 in a high pressure state is supplied to the fuel injection valve 20 of each cylinder through a pipe 14 provided for each cylinder. In addition, the connecting portion 12a between the common rail 12 and the pipe 14 has an orifice (pipe 14) that reduces fuel pulsation (mainly generated at the fuel injection port of the fuel injection valve 20 during injection) transmitted to the common rail 12 through the pipe 14. ) Is provided. Thereby, the pressure pulsation in the common rail 12 is reduced, and fuel can be supplied to each fuel injection valve 20 at a stable pressure. As a means for reducing fuel pulsation, a flow damper, a combination of an orifice and a flow damper, or the like can be applied in addition to the orifice.

  The fuel injection valve 20 injects the fuel stored in the common rail 12 and supplied via the pipe 14 into the combustion chamber of the cylinder. The fuel injection valve 20 injects fuel at the top dead center (TDC) of the cylinder in which the fuel injection valve 20 is installed. Therefore, the phase difference between the crank angle between the pumping timing from the fuel pump 11 to the common rail 12 and the injection timing is constant.

  A nozzle hole 21 is formed at the tip of the nozzle portion of the fuel injection valve 20, and a needle valve that opens and closes the fuel passage to the nozzle hole 21 of the fuel injection valve 20 is accommodated inside the nozzle portion. Fuel injection is stopped when the needle valve is seated on the valve seat around the nozzle hole 21, and fuel is injected from the nozzle hole 21 when the needle valve is separated from the valve seat. This needle valve is driven by an actuator. Specifically, when energization of the actuator is turned on, the needle valve is separated from the valve seat portion, and fuel is injected from the injection hole 21. On the other hand, when energization to the actuator is turned off, the needle valve is seated on the valve seat portion, and fuel injection from the injection hole 21 is stopped.

  Therefore, by controlling the drive period of the actuator, the valve opening period of the fuel injection valve 20 is controlled, and consequently the injection amount injected from the fuel injection valve 20 is controlled. The drive period of the actuator is controlled by the injection command period from the ECU 30. Examples of the actuator include a piezo actuator and an electromagnetic solenoid actuator.

  The ECU 30 is configured as a computer including a CPU 31, a RAM 32, a ROM 33, an EPPROM 34 (registered trademark), an I / O, and a bus line connecting these. The RAM 32 is a main memory, the ROM 33 is a program memory, and the EPPROM 34 (storage means) is a data storage memory (an electrically rewritable nonvolatile memory). The ECU 30 calculates a target injection state composed of the target supply pressure and the target injection amount based on the accelerator pedal operation amount (engine load), the engine speed, and the like. For example, the optimal injection state corresponding to the operation amount of the accelerator pedal and the engine speed is stored as an injection state map. The ECU 30 calculates the target injection state with reference to the injection state map based on the operation amount of the accelerator pedal detected by the accelerator sensor 26 and the engine rotation speed detected by the crank angle sensor 24a. Further, the ECU 30 calculates a command injection period for operating the fuel injection valve 20 to inject the target injection amount at the target supply pressure, and transmits the calculated command injection period to the actuator of the fuel injection valve 20.

  The accelerator sensor 26 is provided in an accelerator pedal (not shown), and outputs an electric signal corresponding to the amount of displacement of the accelerator pedal, and detects the amount of operation of the accelerator pedal by the driver, that is, the accelerator opening. The crank angle sensor 24a is provided on the crankshaft 24, and outputs a crank angle signal for each predetermined crank angle (for example, at a cycle of 30 ° CA), and determines the rotational speed of the crankshaft 24, that is, the rotational speed of the engine. To detect.

  Moreover, ECU30 implement | achieves the function as an inclination calculation means, a timing estimation means, and an injection period correction means, when CPU31 runs the program memorize | stored in ROM33.

  The inclination calculating means calculates the rising inclination of the fuel pressure accompanying the pumping by the fuel pump 11 based on the fuel pressure in the common rail 12 detected every predetermined period by the fuel pressure sensor 13. FIG. 3 shows the fuel pressure in which a fuel pressure sensor 13 detects a pumping waveform indicating fluctuations in fuel pressure accompanying pumping at predetermined intervals. The fuel pressure is detected by the fuel pressure sensor 13 at each timing t1 to t8. The black circles indicate the fuel pressure at which the assumed pumping waveform Wa is detected every predetermined period, and the triangles indicate the fuel pressure at which the assumed pumping waveform Wb is detected every predetermined period. Here, an increase determination threshold is set, and a fuel pressure smaller than the increase determination threshold is set as an initial pressure before being pumped by the fuel pump 11. The increase determination threshold is a value sufficiently smaller than the target supply pressure. The inclination calculation means calculates the increase inclination from the detected values of two or more fuel pressures that are greater than the increase determination threshold and are different from each other among the fuel pressures detected after the initial pressure is detected.

  The timing estimation means estimates the start timing of the pumping by the fuel pump 11 based on the rising slope calculated by the slope calculation means. The timing estimation means calculates the fuel pressure in the common rail 12 from the initial pressure based on the fuel pressure detected after the initial pressure is detected, which is greater than the rise determination threshold, and the rising slope calculated by the slope calculating means. The changing timing is calculated, and the calculated timing is set as the pumping start timing.

  The rotation angle difference of the crankshaft 24 between the pumping start timing estimated by the timing estimation means and the injection timing by the fuel injection valve 20, that is, the crank angle phase difference is stored in the EEPROM 34. Thereby, the phase difference of the crank angle between the pumping timing and the fuel injection timing can be acquired without performing alignment when the fuel pump 11 and the engine are assembled.

  The injection period correction means corrects the command injection period set according to the state of the engine based on the rotation angle difference of the crankshaft 24 stored in the EEPROM 34. In general, the target injection amount and the target supply fuel pressure are set in advance corresponding to the state of the engine (engine load, engine speed), and the period during which the fuel injection valve is operated from the target injection amount and the target supply fuel pressure, that is, A command injection period is set. However, depending on the phase difference of the crank angle between the pumping start timing and the injection timing, the fuel pressure in the common rail 12 may fluctuate from the target supply fuel pressure before injection, and the actual injection amount may be different from the target injection amount. Therefore, a map is prepared of the difference in rotation angle of the crankshaft 24 between the start of pumping and the injection timing and the correction amount of the command injection period. The injection period correction means calculates a correction amount for the command injection period from the rotation angle difference of the crankshaft 24 and the map, and corrects the command injection period according to the calculated correction amount.

  Next, with reference to the flowchart of FIG. 4, the process sequence which estimates the start timing of the pumping by the fuel pump 11 is demonstrated.

  First, as an example, a processing procedure for detecting an assumed pumping waveform Wa (black circle in FIG. 3) every predetermined period and calculating a pumping timing will be described. In S11, the fuel pressure at timing t1 is read. Subsequently, in S12, it is determined whether or not the fuel pressure read in S11 is equal to or higher than an increase determination threshold value. When the fuel pressure is not equal to or higher than the increase determination threshold value (NO), the process returns to S11. When the fuel pressure is equal to or higher than the increase determination threshold value (YES), the process proceeds to S13. Since the fuel pressure read at timing t1 is smaller than the increase determination threshold value, the process returns to S11 and the fuel pressure at timing t2 is read. Subsequently, in S12, it is determined whether or not the fuel pressure read at timing t2 is equal to or higher than an increase determination threshold value. Since the fuel pressure read at the timing t2 is smaller than the increase determination threshold value, the process returns to S11, and the fuel pressure at the timing t3 is read. Subsequently, in S12, it is determined whether or not the fuel pressure read at timing t3 is equal to or higher than the increase determination threshold value. Since the fuel pressure read at timing t3 is larger than the increase determination threshold, the process proceeds to S13.

  Subsequently, in S13, the fuel pressure read at timing t2 is stored as an initial pressure. Since the fuel pressure read at timing t2 is smaller than the rise determination threshold value and the fuel pressure read at timing t3 is greater than the rise determination threshold value, the pumping of fuel to the common rail 12 has started between timing t2 and timing t3. I understand. That is, since the time t2 is before the start of the pumping, the fuel pressure read at the timing t2 becomes the initial pressure before the fuel pressure increases with the pumping.

  Subsequently, in S14, the fuel pressure read at timing t3 is stored. The fuel pressure read at timing t3 is a fuel pressure that has risen from the initial pressure with the pumping. Subsequently, in S15, the fuel pressure at timing t4 is read and stored. The fuel pressure read at timing t4 is a fuel pressure that is higher than the fuel pressure read at timing t3 due to the pressure feeding.

  Subsequently, in S16, the rising slope of the fuel pressure accompanying the pumping is calculated from the fuel pressure at the timing t3 stored in S14 and the fuel pressure at the timing t4 stored in S15.

  Subsequently, in S17, the pumping start timing is calculated from the initial pressure stored in S13 and the rising slope calculated in S16. Specifically, an intersection of an initial pressure line (two-dot chain line in FIG. 3) indicating the initial pressure stored in S13 and a pressure increase line (a one-dot chain line in FIG. 3) passing through the fuel pressure read at timing t3 and timing t4, The start timing of pumping. The calculated pumping start timing (marked with x in FIG. 2) is between timing t2 and timing t3 and is closer to timing t2. This process is complete | finished above.

  As a next example, a processing procedure for detecting an assumed pumping waveform Wb (triangle in FIG. 3) every predetermined period and calculating pumping timing will be described. In this case, it is determined that the pressure read from timing t1 to timing t3 is smaller than the increase determination threshold value. In S12, it is determined that the fuel pressure read at timing t4 is equal to or higher than the increase determination threshold (YES), and the fuel pressure read at timing t3 is stored as an initial pressure in S13. In this case, it can be seen that fuel pumping to the common rail 12 has started between timing t3 and timing t4.

  Subsequently, in S14, the fuel pressure read at timing t4 is stored. Subsequently, in S15, the fuel pressure at timing t5 is read and stored.

  Subsequently, in S16, the rising slope of the fuel pressure accompanying pumping is calculated from the fuel pressure at timing t4 stored in S14 and the fuel pressure at timing t5 stored in S15.

  Subsequently, in S17, the intersection of the initial pressure line indicating the initial pressure stored in S13 and the pressure rise line (two-dot chain line in FIG. 3) passing through the fuel pressure read in at timing t4 and timing t5 is determined as the pumping start timing. And The calculated pumping start timing (marked x in FIG. 3) is between timing t3 and timing t4, and is immediately after timing t3. That is, in the pumping waveform Wb, the pumping start timing is later than in the pumping waveform Wa. Further, the phase difference of the crank angle between the pumping start timing and the injection timing is smaller in the pumping waveform Wb than in the pumping waveform Wa. This process is complete | finished above.

  According to the present embodiment described above, the following effects are obtained.

  The fuel pressure in the common rail 12 is detected by the fuel pressure sensor 13 every predetermined period, and the rising slope of the fuel pressure accompanying pumping is calculated based on the detected fuel pressure. Then, based on the calculated increase slope of the fuel pressure, the pumping start timing is estimated, and the rotational angle difference of the crankshaft 24 between the estimated pumping start timing and the injection timing is stored. Therefore, the crank at the pumping start timing and the injection timing is estimated by estimating the pumping start timing by the fuel pump 11 without previously aligning the key of the pump shaft and the predetermined tooth of the internal combustion engine side gear. The phase difference of the angle can be acquired.

  The timing at which the fuel pressure starts to rise from the detected value of the fuel pressure in the common rail 12 that has risen from the initial pressure due to the pumping by the fuel pump 11 and the rising slope that is calculated based on the fuel pressure detected every predetermined period; That is, the start timing of the pressure feeding can be calculated.

  ・ If the rising slope is calculated using the fuel pressure detected before the start timing of pumping, there is a risk that it will deviate from the rising slope of the actual fuel pressure, but only the detected value of the fuel pressure that has risen from the initial pressure is used. Since the rising slope of the fuel pressure is calculated, the rising slope can be calculated with high accuracy.

  By correcting the command injection period set according to the engine state based on the phase difference of the crank angle between the pumping start timing and the injection timing, it is possible to reduce the variation in the injection amount.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows.

  -ECU30 may implement | achieve the function of the valve opening period correction | amendment means which correct | amends the valve opening period of the suction | inhalation adjustment valve 60 instead of the injection period correction | amendment means. Generally, a target injection amount and a target supply fuel pressure are set in advance corresponding to the state of the engine, and a pumping amount by the fuel pump 11, that is, a valve opening period of the intake adjustment valve 60 is set corresponding to the target supply fuel pressure. ing. However, depending on the phase difference of the crank angle between the pumping start timing and the injection timing, the fuel pressure of the common rail 12 may fluctuate from the target supply pressure before injection, and the injection amount may vary. Therefore, the set valve opening period of the intake adjustment valve 60 is corrected based on the phase difference of the crank angle between the pumping start timing and the injection timing. Specifically, a map of the rotation angle difference of the crankshaft 24 at the start timing and the end timing of pumping and the correction amount of the valve opening period is prepared, and the valve opening period is corrected using the prepared map. Thereby, the fuel pressure of the common rail 12 can be made the target supply fuel pressure at the time of injection. Furthermore, it is possible to suppress the fuel pressure of the common rail 12 from overshooting the pressure resistance of the fuel pump 11.

  The pressure feed amount to the common rail 12 may be adjusted by adjusting the valve opening period of the suction valve 53 or the discharge valve 54. In this case, the valve opening period correction means corrects the valve opening period of the intake valve 53 or the discharge valve 54.

  The timing estimation unit may estimate the pumping end timing from the pumping start timing and the pumping period determined from the driving cycle of the plunger 51. Further, the rotation angle difference of the crankshaft 24 between the pumping end timing and the injection timing may be stored in the EEPROM 34.

  -A fuel-injection apparatus may be mounted not only in a diesel engine but in a direct-injection gasoline engine. The fuel injection device may be mounted on an engine other than the four cylinders. Further, the fuel injection device is not limited to a vehicle engine, and may be mounted on an engine such as a ship.

  DESCRIPTION OF SYMBOLS 11 ... Fuel pump, 12 ... Common rail, 13 ... Fuel pressure sensor, 20 ... Fuel injection valve, 24 ... Crankshaft, 30 ... ECU, 34 ... EEPROM.

Claims (5)

A pressure vessel (12) for storing fuel in a high pressure state;
A fuel pump (11) connected to a crankshaft (24) of an internal combustion engine and driven to pump fuel to the animal pressure vessel;
A fuel injection valve (20) for injecting the fuel stored in the animal pressure vessel;
A fuel pressure detecting means (13) for detecting the fuel pressure in the animal pressure vessel every predetermined period;
An inclination calculating means (30) for calculating an increase inclination of the fuel pressure accompanying the pumping by the fuel pump based on the fuel pressure detected every predetermined period by the fuel pressure detecting means;
Timing estimating means (30) for estimating the timing of pumping by the fuel pump based on the rising slope of the fuel pressure calculated by the slope calculating means;
A fuel injection device comprising: a storage means (34) for storing a difference in rotation angle of the crankshaft between the pumping timing estimated by the timing estimation means and the injection timing by the fuel injection valve. A fuel pressure smaller than a threshold value among fuel pressures detected at predetermined intervals by the fuel pressure detection means is set as an initial pressure before pumping by the fuel pump,
The timing estimation means includes a fuel pressure that is greater than the threshold value among fuel pressures detected after the detection of the initial pressure by the fuel pressure detection means, and the rising slope calculated by the slope calculation means. The fuel injection device according to claim 1, wherein a timing at which the fuel pressure in the animal pressure vessel changes from the initial pressure is calculated, and the calculated timing is used as a start timing of pressure feeding by the pump.   The inclination calculating means calculates the increasing inclination from fuel pressures that are greater than the threshold value and different from each other among fuel pressures detected after the initial pressure is detected by the fuel pressure detecting means. The fuel injection device described.   The injection period correcting means (30) for correcting a command injection period set in accordance with the state of the internal combustion engine based on a rotation angle difference of the crankshaft stored in the storage means. The fuel injection device according to any one of the above. The fuel pump includes a plunger (51) for pumping fuel, and an adjustment valve (60) for adjusting the amount of fuel pumped to the animal pressure vessel by the plunger,
A valve opening period correcting means (30) for correcting a valve opening period of the regulating valve set according to a state of the internal combustion engine based on a rotation angle difference of the crankshaft stored in the storage means. Item 5. The fuel injection device according to any one of Items 1 to 4.

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