WO2010146896A1 - Control apparatus for diesel engine - Google Patents

Control apparatus for diesel engine Download PDF

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Publication number
WO2010146896A1
WO2010146896A1 PCT/JP2010/052513 JP2010052513W WO2010146896A1 WO 2010146896 A1 WO2010146896 A1 WO 2010146896A1 JP 2010052513 W JP2010052513 W JP 2010052513W WO 2010146896 A1 WO2010146896 A1 WO 2010146896A1
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WO
WIPO (PCT)
Prior art keywords
pressure
diesel engine
crank angle
fuel
fuel injection
Prior art date
Application number
PCT/JP2010/052513
Other languages
French (fr)
Japanese (ja)
Inventor
博隆 金子
Original Assignee
ボッシュ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ボッシュ株式会社 filed Critical ボッシュ株式会社
Priority to JP2011519627A priority Critical patent/JP5140191B2/en
Publication of WO2010146896A1 publication Critical patent/WO2010146896A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N19/00—Starting aids for combustion engines, not otherwise provided for
    • F02N19/005—Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N11/00—Starting of engines by means of electric motors
    • F02N11/08—Circuits or control means specially adapted for starting of engines
    • F02N11/0814—Circuits or control means specially adapted for starting of engines comprising means for controlling automatic idle-start-stop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N19/00—Starting aids for combustion engines, not otherwise provided for
    • F02N19/005—Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation
    • F02N2019/008—Aiding engine start by starting from a predetermined position, e.g. pre-positioning or reverse rotation the engine being stopped in a particular position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
    • F02N99/00—Subject matter not provided for in other groups of this subclass
    • F02N99/002—Starting combustion engines by ignition means
    • F02N99/006—Providing a combustible mixture inside the cylinder
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the present invention relates to a control device for a diesel engine, and more particularly, to a control device for a diesel engine used for controlling a diesel engine capable of idling stop control.
  • a plurality of fuel injection valves are connected and a common rail for storing high-pressure fuel is provided, and energization control of the fuel injection valves is performed in a state where high-pressure fuel pressurized by a high-pressure pump is supplied to each fuel injection valve
  • a high-pressure pump is supplied to each fuel injection valve
  • some internal combustion engines mounted mainly on vehicles are configured to be capable of idling stop control for stopping the internal combustion engine when the internal combustion engine is idle for the purpose of improving fuel consumption and reducing exhaust gas.
  • the internal combustion engine is stopped when a predetermined idling stop condition is satisfied when the internal combustion engine is stopped, and the internal combustion engine is restarted when a predetermined restart condition is satisfied.
  • Fuel injection valves used for pressure accumulating fuel injection devices include a magnet injector mainly equipped with an electromagnetic solenoid and a piezo injector equipped with a piezo element.
  • a leak passage for returning low-pressure fuel to the fuel tank in addition to a back pressure relief passage for releasing the back pressure loaded on the rear end side of the nozzle needle that opens and closes the injection hole due to its structure May be provided.
  • the high-pressure fuel supplied from the common rail to the fuel injection valve is sent to the injection hole on the tip side of the nozzle needle and is sent to the back pressure chamber in order to apply a back pressure to the nozzle needle.
  • a part of the high-pressure fuel sent to the injection hole side leaks to the low-pressure side in the fuel injection valve through the periphery of the nozzle needle, in addition to being injected from the injection hole. Since the leaked fuel cannot move to another high pressure side due to the pressure difference, a leak passage is provided in the fuel injection valve so that the leaked fuel is returned from the fuel injection valve to the fuel tank. ing.
  • the pressure that allows normal injection of high-pressure fuel after cranking starts when the diesel engine is restarted (below) It takes time until the rail pressure returns to “injectable pressure”. That is, even if the crank angle is adjusted as in the control device of the internal combustion engine of Patent Document 1 and the restart condition is satisfied, the normal pressure of the high-pressure fuel is normal even if the crank angle is at a predetermined position suitable for restart. It takes time for the rail pressure to rise above the pressure at which injection is possible, and it takes time for the diesel engine to restart.
  • an object of the present invention is to provide a diesel engine control device that enables a diesel engine to be restarted in a short time when the diesel engine is restarted after being stopped by idling stop control.
  • a high-pressure pump that is driven as the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and a plurality that is connected to the common rail and injects fuel into the cylinder of the diesel engine.
  • a diesel engine control device for controlling a diesel engine equipped with a pressure-accumulation fuel injection device having a fuel injection valve, and stopping a diesel engine when a predetermined idling stop condition is satisfied,
  • An idling stop control unit that controls to restart the diesel engine when the restart condition is satisfied, and a pressure at which the pressure in the common rail can normally inject high-pressure fuel when the diesel engine is restarted while the diesel engine is stopped Diesel engine to reach more quickly Of the crank angle control unit for controlling shifting of the crank angle, it is provided control apparatus for a diesel engine comprising: a, it is possible to solve the problems described above.
  • the crank angle control unit responds to the maximum number of pumping of the high-pressure pump necessary to make the pressure in the common rail equal to or higher than the pressure at which high-pressure fuel can be normally injected. Thus, it is preferable to determine a target position for shifting the crank angle.
  • the crank angle control unit determines a target position to shift the crank angle according to the lift position of the plunger of the high-pressure pump at the fuel injection timing at the time of restart. It is preferable.
  • the crank angle control unit sets the target position at which normal injection of high-pressure fuel from the fuel injection valve is possible when the diesel engine is restarted for each of the plurality of fuel injection valves.
  • the crank angle is shifted to a target position that minimizes the amount of shift of the crank angle among the plurality of calculated target positions.
  • the crank angle control unit is It is preferable to selectively perform control for advancing or retreating the crank angle with the state where the high pressure pump is in the fuel pressure stroke as the target position.
  • the crank angle control unit it is preferable to perform control to advance or retract the crank angle with the target position being the state where the high-pressure pump is in the fuel intake stroke so that the maximum number of pumping times of the pump is ensured.
  • the diesel engine control device includes a rail pressure detection unit that detects the pressure in the common rail, and the crank angle control unit is detected when the restart condition is satisfied.
  • the target position for shifting the crank angle is preferably determined based on the difference between the pressure in the common rail and the pressure at which normal injection of high-pressure fuel is possible.
  • the diesel engine control device includes a rail pressure detection unit that detects the pressure in the common rail, and the crank angle control unit is installed in the common rail while the diesel engine is stopped. It is preferable to perform control to shift the crank angle when the pressure becomes less than a pressure at which high pressure fuel can be normally injected.
  • the crank angle control unit is configured so that the diesel engine performs the compression stroke when the pressure in the common rail when the restart condition is satisfied is equal to or higher than the pressure at which high pressure fuel can be normally injected. It is preferable to perform control to shift the crank angle so as to start from.
  • the diesel engine is set so that the rail pressure quickly reaches the injectable pressure when the diesel engine is cranked during the restart while the diesel engine is stopped by the idling stop control.
  • the crank angle of the engine is shifted. Therefore, the diesel engine is restarted in a state where the lift position of the plunger of the high-pressure pump is at a position where the rail pressure quickly reaches the injectable pressure or more. Therefore, normal injection of high-pressure fuel becomes possible immediately after the restart condition is satisfied, and the time until the diesel engine is restarted is shortened.
  • the crank angle is shifted in accordance with the maximum number of pumping times of the high-pressure pump necessary for making the rail pressure equal to or higher than the injectable pressure (hereinafter referred to as “required maximum pumping frequency”). If the target position is determined, normal injection of high-pressure fuel into the cylinder can be promptly performed according to the required maximum number of pumping times.
  • the fuel injection timing and Normal injection of high-pressure fuel into the cylinder can be quickly performed in accordance with the relationship with the lift position of the plunger of the high-pressure pump.
  • the crank angle target position is calculated for each of the plurality of fuel injection valves, and the crank angle is shifted to the target position where the amount of shifting the crank angle is minimized.
  • the time for shifting the crank angle can be shortened, and the load for shifting the crank angle is reduced.
  • the crank angle is advanced with the target position being the state where the high-pressure pump is in the fuel pressure stroke.
  • the amount of shifting the crank angle can be minimized by controlling the angle or retraction. That is, when the low-pressure pump is driven without depending on the rotational state of the diesel engine, the fuel is reliably supplied to the pressurizing chamber of the high-pressure pump by operating the low-pressure pump even before starting the diesel engine. Therefore, the crank angle can be freely advanced or retracted.
  • the low-pressure pump when the low-pressure pump is a pump driven depending on the rotational state of the diesel engine, the high-pressure pump is fueled to ensure the maximum number of pumping times of the high-pressure pump.
  • the rail pressure By controlling the crank angle to be advanced or retreated with the state in the intake stroke as the target position, the rail pressure reaches the injection possible pressure more quickly while minimizing the amount of shift of the crank angle.
  • the crank angle can be shifted to the correct position. That is, when the low-pressure pump is a pump driven depending on the rotational state of the diesel engine, the fuel is not supplied to the pressurizing chamber even if the crank angle is retracted.
  • the target position that ensures the maximum number of pumping times is preferentially selected and the crank angle is shifted.
  • the rail pressure becomes equal to or higher than the injectable pressure. Since the crank angle is shifted according to the required number of pumping times of the high-pressure pump, the rail pressure becomes equal to or higher than the injectable pressure below the required maximum number of pumping times, and the fuel can be quickly injected into the cylinder.
  • control device for a diesel engine when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped, the control for shifting the crank angle is performed, so that the rail pressure is sufficiently secured. In this state, it is not necessary to perform control for shifting the crank angle in order to make the rail pressure reach more quickly than the injectable pressure.
  • the crank angle of the diesel engine is shifted so that the diesel engine starts from the compression stroke. Therefore, in a state where the rail pressure is sufficiently secured, after the restart condition is established, the fuel is quickly injected into the cylinder of the diesel engine and an explosion occurs in the cylinder, so that the diesel engine can be started more quickly. It becomes possible.
  • crank angle shift control in case rail pressure is maintained until engine restart conditions are satisfied. It is a control flowchart which shows an example of the control method of a diesel engine. It is a figure for demonstrating crank angle shift control in case rail pressure falls during the stop of the diesel engine concerning 2nd Embodiment.
  • FIG. 1 shows a diesel engine 40 that is controlled by the control device 70 of the diesel engine 40 according to an embodiment of the present invention, and a pressure accumulation provided in the diesel engine 40. 1 shows a schematic configuration of a fuel injection device 50.
  • the piston 42 reciprocates in the cylinder 41 as the crankshaft 43 rotates, and diesel fuel is injected into the cylinder 41 during the compression stroke, causing an explosion in the cylinder 41 and pushing down the piston 42. Then, the crankshaft 43 is driven by being further rotated.
  • the diesel engine 40 is provided with a starter 44 as a crank angle adjusting means for forcibly rotating the crankshaft 43 and a crank angle sensor 45 for detecting a crank angle that is a rotation phase of the crankshaft 43. ing.
  • a pressure accumulation type fuel injection device 50 for injecting fuel into the cylinder 41 of the diesel engine 40 includes a fuel tank 1, an electric low-pressure pump 2, a high-pressure pump 5, a common rail 10, a fuel injection valve 13, and the like. It is provided as the main element.
  • the pressurizing chamber 5a of the electric low pressure pump 2 and the high pressure pump 5 is connected by a low pressure fuel passage 18, and the high pressure pump 5 and the common rail 10, and the common rail 10 and the fuel injection valve 13 are connected by high pressure fuel passages 37 and 39.
  • fuel leak passages 30a to 30c for returning discharged fuel to the fuel tank 1 are connected to the high pressure pump 5, the common rail 10, the fuel injection valve 13, and the like.
  • the electric low-pressure pump 2 pumps the low-pressure fuel in the fuel tank 1 to the pressurizing chamber 5 a of the high-pressure pump 5 through the low-pressure fuel passage 18.
  • An electric low-pressure pump 2 shown in FIG. 1 is an in-tank electric low-pressure pump provided in a fuel tank 1 in which low-pressure fuel is stored. The electric low-pressure pump 2 is driven by a voltage supplied from a battery and corresponds to the supply voltage. A low pressure fuel with a predetermined flow rate is pumped at the output.
  • the high-pressure pump 5 is pumped by the electric low-pressure pump 2 and pressurized by the plunger 7 with the low-pressure fuel introduced into the pressurizing chamber 5 a via the fuel intake valve 6, and via the fuel discharge valve 9 and the high-pressure fuel passage 37. High pressure fuel is pumped to the common rail 10.
  • the low-pressure fuel sent into the high-pressure pump 5 once flows into the cam chamber 16 in which the cam 15 is accommodated, and is further sent from there to the pressurizing chamber 5a. .
  • a flow control valve 8 is provided in the middle of the low pressure fuel passage 18 connecting the cam chamber 16 and the pressurizing chamber 5a, and is supplied to the pressurizing chamber 5a according to the required rail pressure and the required injection amount.
  • the flow of low pressure fuel is adjusted.
  • the discharge amount of the high-pressure fuel from the high-pressure pump 5 is adjusted by adjusting the flow rate of the low-pressure fuel supplied to the pressurizing chamber 5a.
  • a pressure adjustment valve 14 connected to a passage branched from the low-pressure fuel flow path 18 and arranged in parallel with the flow control valve 8. Further, 14 is connected to a fuel leak passage 30 a communicating with the fuel tank 1.
  • the pressure regulating valve 14 is an overflow valve that is opened when the difference between the front and rear pressures, that is, the pressure in the low pressure fuel passage 18 and the pressure in the fuel leak passage 30a exceeds a predetermined value. ing.
  • the cam 15 that drives the high-pressure pump 5 is fixed to a camshaft connected to the crankshaft 43 of the diesel engine 40 via a gear, and the rotational speed of the cam 15 is proportional to the rotational speed of the diesel engine 40. Further, in the high pressure pump 5 of the accumulator fuel injection device 50 shown in FIG. 1, the two plungers 7 are pushed up by the cams 15 having two peaks, and the low pressure fuel is pressurized in the two pressurizing chambers 5a. Thus, high-pressure fuel is pumped from each pressurizing chamber 5 a to the common rail 10. Therefore, the number of pumping times of the high-pressure pump 5 per rotation of the cam 15 is four.
  • the common rail 10 accumulates the high-pressure fuel pumped from the high-pressure pump 5 and supplies the high-pressure fuel to the plurality of fuel injection valves 13 connected via the high-pressure fuel passage 39.
  • a rail pressure sensor 21 and a pressure control valve 12 are attached to the common rail 10.
  • an electromagnetic proportional control valve is used as the pressure control valve 12, the amount of fuel leaked from the common rail 10 to the fuel leak passage 30 b is adjusted, and the rail pressure is adjusted according to the amount of leak.
  • a rail pressure signal detected by the rail pressure sensor 21 provided in the common rail 10 is sent to the control device 70.
  • the control device 70 controls the pressure control valve 12 provided in the common rail 10 or the flow rate control valve 8 provided in the high-pressure pump 5 so that the detected rail pressure becomes the target rail pressure.
  • the fuel injection valve 13 connected to the common rail 10 includes a nozzle body provided with an injection hole and a nozzle needle that closes the injection hole, and the back pressure acting on the rear end side of the nozzle needle is released to release the injection hole. Is opened, the high-pressure fuel supplied from the common rail 10 is injected into the cylinder 41 of the diesel engine 40.
  • the fuel injection valve 13 is, for example, an electromagnetic control type magnet injector provided with an electromagnetic solenoid as a back pressure control unit, or an electrostrictive type piezo injector provided with a piezo element as a back pressure control unit.
  • the rail pressure is equal to or higher than the injectable pressure, and normal injection is possible in a state where high-pressure fuel is supplied.
  • a fuel injection valve having a structure in which a leak passage is provided in addition to a passage for releasing back pressure is used as the fuel injection valve 13 .
  • Control Device 70 of Diesel Engine The control device 70 of the diesel engine 40 of the present embodiment is based on the discharge amount control of the high pressure pump 5 by the flow rate control valve 8 provided on the high pressure pump 5 and the pressure control valve 12 provided on the common rail 10. High pressure discharge control, fuel injection control into the cylinder 41 of the diesel engine 40 by the fuel injection valve 13, idling stop control of the diesel engine 40, and crank angle adjustment control of the diesel engine 40 are performed.
  • FIG. 2 is a functional block diagram showing a part related to idling stop control and crank angle adjustment control in the configuration of the control device 70 of the diesel engine 40 of the present embodiment.
  • the control device 70 is configured around a microcomputer having a known configuration, and includes an idling stop control unit 71, a crank angle detection unit 73, a rail pressure detection unit 75, a fuel injection valve control unit 76, And a crank angle control unit 77. Specifically, each of these units is realized by executing a program by a microcomputer.
  • the control device 70 includes a rail pressure sensor 21 provided in the common rail 10, a crank angle sensor 45 provided in the diesel engine 40, a vehicle speed sensor that detects a vehicle speed V provided in the vehicle, and an accelerator pedal operation amount Acc. Accelerator sensor for detecting, brake sensor for detecting brake pedal operation amount Brk, clutch sensor for detecting clutch position Cp of transmission, shift position sensor for detecting shift position Gp of transmission, etc. Switches and sensors are connected.
  • the fuel injection valve control unit 76 performs drive control of the fuel injection valve 13.
  • the fuel injection valve 13 of this embodiment is a magnet injector provided with an electromagnetic solenoid, and the fuel injection valve control unit 76 energizes the electromagnetic solenoid according to the fuel injection amount Q calculated according to the operating state of the diesel engine 40.
  • the control signal S1 is output to control the opening and closing of the injection hole of the fuel injection valve 13.
  • the crank angle detector 73 reads the crank angle sensor signal Sc and detects the crank angle Ca.
  • the detected crank angle Ca is sent to the crank angle control unit 77.
  • the rail pressure detector 75 reads the signal Sp of the rail pressure sensor 21 and detects the rail pressure Pr.
  • the detected rail pressure Pr is sent to the idling stop control unit 71 and the crank angle control unit 77.
  • the idling stop control unit 71 includes an engine stop determination unit 71a and an engine restart determination unit 71b. Idling stop control suppresses fuel consumption or exhausts during situations where the vehicle stops for a short time, such as when the vehicle is waiting for a signal, while a person is getting on or off, or when loading or unloading an object. In order to suppress gas emission, the diesel engine 40 is temporarily stopped while the switch of the diesel engine 40 is kept on.
  • the configurations of the engine stop determination unit 71a and the engine restart determination unit 71b are not particularly limited, but in the example of the control device 70 of the present embodiment, the engine stop determination unit 71a is configured such that the rotational speed Ne of the diesel engine 40 is Read information such as accelerator pedal operation amount Acc, brake pedal operation amount Brk, transmission clutch position Cp, transmission shift position Gp, etc., and whether or not the idling stop condition set in advance based on these information is satisfied Is determined.
  • an instruction signal S2 is sent to the fuel injection valve control unit 76 to interrupt the fuel injection, and a signal Ses indicating that the idling stop condition is satisfied is sent to the engine restart determining unit 71b. And sent to the crank angle control unit 77.
  • the engine restart determination unit 71b of the control device 70 of the present embodiment receives the signal Ses indicating that the idling stop condition is satisfied from the engine stop determination unit 71a, the accelerator pedal operation amount Acc, the brake pedal operation Information such as the amount Brk, the clutch position Cp of the transmission, the shift position Gp of the transmission, etc. is read, and based on these information, it is determined whether a preset restart condition is satisfied.
  • a signal Srs indicating that the restart condition is satisfied is sent to the crank angle control unit 77, and a signal S3 permitting fuel injection is sent to the fuel injection valve control unit 76.
  • the crank angle control unit 77 outputs an operation signal S4 to the starter 44 as crank angle adjusting means for shifting the rotation phase of the crankshaft 43.
  • the crank angle control unit 77 of the control device 70 of the present embodiment injects the rail pressure Pr when the rail pressure Pr is less than the injectable pressure Pr0 when the restart condition is satisfied after the diesel engine 40 is stopped by the idling stop control.
  • An operation signal S4 for shifting the crank angle Ca of the diesel engine 40 is output to the starter 44 so as to quickly reach the possible pressure Pr0 or higher.
  • crank angle control unit 77 of the control device 70 of the present embodiment is configured so that the diesel engine 40 is diesel-powered when the rail pressure Pr is equal to or higher than the injectable pressure Pr0 when the restart condition is satisfied after the diesel engine 40 is stopped by the idling stop control.
  • An operation signal Sst for shifting the crank angle Ca of the diesel engine 40 is output to the starter 44 so that cranking is started from a position where a necessary compression stroke is performed before fuel injection in the engine 40.
  • the diesel engine 40 is started on the condition that the diesel engine 40 is in the compression stroke and the rail pressure Pr is equal to or higher than the injectable pressure Pr0.
  • the rail pressure Pr becomes equal to or higher than the injectable pressure Pr0 than when the diesel engine 40 is in the compression stroke.
  • the rail pressure Pr becomes less than the injectable pressure Pr0 during the stop, the rapid increase of the rail pressure Pr is prioritized.
  • crank angle adjustment method performed by the control device 70 while the diesel engine 40 is stopped by idling stop control will be specifically described.
  • the control device 70 of the present embodiment promptly causes the rail pressure Pr to be injectable during restart.
  • the crank angle Ca is shifted so as to reach Pr0 or more (control mode 1).
  • the control device 70 of the present embodiment performs the compression stroke necessary for fuel injection before restarting when the rail pressure Pr is maintained at the injectable pressure Pr0 or higher even when the diesel engine 40 is stopped.
  • the crank angle Ca is shifted so that cranking is started from the position where it is positioned (control mode 2).
  • FIGS. 3 to 6 are diagrams for explaining a crank angle adjustment method executed when the rail pressure Pr becomes lower than the injectable pressure Pr0 while the diesel engine 40 is stopped.
  • the horizontal axis represents the crank angle Ca of the diesel engine 40
  • the vertical axis represents the lift amount Lpl of the plunger 7 of the high-pressure pump 5.
  • This is an example of the accumulator type fuel injection device 50 in which the maximum number of times of pumping from the high-pressure pump 5 is required until the rail pressure Pr is changed from atmospheric pressure to the injectable pressure Pr0 or more.
  • Each figure shows an example in which the number of cylinders of the diesel engine 40 is four, and cylinders in which fuel is injected at each fuel injection timing are indicated by # 1 to # 4.
  • the stroke in which the lift position of the plunger is increased represents the fuel pressure feed stroke
  • the stroke in which the lift amount of the plunger is decreased represents the fuel intake stroke.
  • FIG. 3 shows that the plunger 7 of the high-pressure pump 5 reciprocates twice while the crankshaft 43 of the diesel engine 40 rotates once (360 ° rotation), and fuel injection is performed near the top dead center of the plunger 7.
  • FIG. 4 shows that the plunger 7 of the high-pressure pump 5 reciprocates twice while the crankshaft 43 of the diesel engine 40 makes one rotation (360 ° rotation), and fuel injection is performed near the bottom dead center of the plunger 7.
  • FIG. 3 shows that the plunger 7 of the high-pressure pump 5 reciprocates twice while the crankshaft 43 of the diesel engine 40 rotates once (360 ° rotation), and fuel injection is performed near the top dead center of the plunger 7.
  • FIG. 4 shows that the plunger 7 of the high-pressure pump 5 reciprocates twice while the crankshaft 43 of the diesel engine 40 makes one rotation (360 ° rotation), and fuel injection is performed near the bottom dead center of the plunger 7.
  • an example of a pressure accumulation type fuel injection device in which the fuel injection timing and the reciprocation of the plunger 7 are synchronized
  • 5 and 6 show that the plunger 7 of the high-pressure pump 5 reciprocates once and a half while the crankshaft 43 of the diesel engine 40 makes one rotation (360 ° rotation), and the plunger at the fuel injection timing every time.
  • 7 shows an example of a pressure accumulating fuel injection device having different lift positions.
  • control device 70 of the present embodiment performs cranking so that the rail pressure Pr quickly reaches the injectable pressure Pr0 or more when the diesel engine 40 is restarted while the diesel engine 40 is stopped by the idling stop control. Control to shift the corner Ca.
  • the target position Catgt when shifting the crank angle Ca differs depending on the lift position of the plunger 7 when fuel injection is performed.
  • the plunger 7 wants to start fuel injection at the crank angle Ca at the top dead center, in order to ensure that the number of pumps of the high-pressure pump 5 is 1.5, the fuel injection A crank angle Ca displacement of 225 ° or more is required by the timing.
  • the low-pressure pump that supplies fuel to the pressurizing chamber 5a of the high-pressure pump 5 is a pump that is driven without depending on the rotational speed of the diesel engine 40, such as the electric low-pressure pump 2 of the accumulator fuel injection device 50 of the present embodiment. Can fill the pressurizing chamber 5a with fuel even before the diesel engine 40 is started. Therefore, when such a low-pressure pump is provided, the target position Catgt for shifting the crank angle Ca may be in the fuel pressure feed stroke of the high-pressure pump 5.
  • the diesel engine 40 is stopped at a position where the crank angle Ca is 450 ° by idling stop control.
  • the target position of the crank angle Ca is set in order to ensure that the number of pumps of the high-pressure pump 5 is 1.5. It is necessary to set Catgt to 315 ° and shift the crank angle Ca by -135 °. Further, if it is desired to start fuel injection from the cylinder # 1 at which the fuel injection timing comes next, in order to ensure that the number of pumping times of the high pressure pump 5 is 1.5 pumping, the target position of the crank angle Ca is set.
  • the amount by which the crank angle Ca is shifted is minimized when fuel injection is started from the cylinder # 1, so the target position Catgt (A) of the crank angle Ca is set to 495 °, and the diesel engine 40 The crank angle Ca is shifted by the time of restart.
  • the time for shifting the crank angle Ca is minimized, the load for shifting the crank angle Ca is reduced, and normal injection of high-pressure fuel in the minimum time after cranking is started when the diesel engine 40 is restarted. It becomes possible.
  • the diesel engine 40 is stopped at a position B where the crank angle Ca is 360 ° by the idling stop control.
  • the target position Catgt of the crank angle Ca it is necessary to set the target position Catgt of the crank angle Ca to 315 ° and shift the crank angle Ca by ⁇ 45 °.
  • crank angle Ca it is necessary to set the target position Catgt of crank angle Ca to 675 ° and shift crank angle Ca by + 315 °, and if it is desired to start fuel injection from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 855 ° and shift the crank angle Ca by + 495 °.
  • the amount of shift of the crank angle Ca is minimized when fuel injection is started from the cylinder # 2, so the target position Catgt (B) of the crank angle Ca is set to 315 °, and the diesel engine 40 The crank angle Ca is shifted by the time of restart.
  • the time for shifting the crank angle Ca is minimized, the load for shifting the crank angle Ca is reduced, and normal injection of high-pressure fuel in the minimum time after cranking is started when the diesel engine 40 is restarted. It becomes possible.
  • the diesel engine 40 is stopped at a position where the crank angle Ca is 405 ° by the idling stop control.
  • the target position Catgt of the crank angle Ca it is necessary to set the target position Catgt of the crank angle Ca to 315 ° and shift the crank angle Ca by ⁇ 90 °.
  • crank angle Ca it is necessary to set the target position Catgt of crank angle Ca to 675 ° and shift crank angle Ca by + 270 °, and if it is desired to start fuel injection from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 855 ° and shift the crank angle Ca by + 450 °.
  • the amount by which the crank angle Ca is shifted is minimized when the fuel injection is started from the cylinder # 2 or the cylinder # 1, so the target position Catgt (C) of the crank angle Ca is set to 315 ° or 495 °.
  • the crank angle Ca is shifted until the diesel engine 40 is restarted.
  • the time for shifting the crank angle Ca is minimized, the load for shifting the crank angle Ca is reduced, and normal injection of high-pressure fuel in the minimum time after cranking is started when the diesel engine 40 is restarted. It becomes possible.
  • crank angle Ca (540 °) at which the plunger 7 is at the bottom dead center in the cylinder # 2 of the cylinders # 1 to # 4
  • the high pressure pump In order to ensure that the number of times of pumping 5 is 1.5 pumping, displacement of the crank angle Ca of 315 ° or more is required before the fuel injection timing.
  • the fuel is produced at the position where the plunger 7 is being lowered (crank angle 540 °) as in the example of FIG. If it is desired to start fuel injection in the cylinder # 2 where injection is performed, a crank angle Ca of 360 ° or more is required before the fuel injection timing in order to ensure that the number of pumps of the high-pressure pump 5 is 1.5. Displacement is required. Further, as in the example of FIG.
  • crank angle 720 ° the high-pressure pump 5 In order to ensure that the number of pumping times is 1.5, the crank angle Ca must be displaced by 300 ° or more before the fuel injection timing.
  • the high-pressure pump 5 pumps the fuel. In order to ensure that the number of times is 1.5, the crank angle Ca must be displaced by 300 ° or more before the fuel injection timing.
  • the high-pressure pump 5 In order to ensure that the number of pumping times is 1.5, the crank angle Ca must be displaced by 420 ° or more before the fuel injection timing.
  • the displacement of the crank angle Ca required to ensure the maximum number of pumping times of the high-pressure pump 5 that enables normal injection of high-pressure fuel at each fuel injection timing is required for the fuel injection timing and the like. It depends on the maximum number of pumping times of the high-pressure pump 5. Therefore, based on the crank angle Ca when the diesel engine 40 is stopped and the required displacement of the crank angle Ca, the target position Catgt is set so that the amount of shifting the crank angle Ca is minimized, and the crank angle Ca is It is shifted.
  • the amount of shifting the crank angle Ca to the target position Catgt is small, and the load on the battery and the starter 44 is reduced. Since the load of the battery is reduced, the amount of power that the alternator should generate during the next driving cycle is reduced, so that the torque required for the operation of the alternator is reduced and the fuel efficiency is improved. Further, if the crank angle Ca is shifted after the restart condition is established, the time for shifting the crank angle Ca can be shortened, so that the diesel engine 40 can be restarted quickly.
  • the accumulator fuel injection device 50 used in the description of the present embodiment includes the electric low-pressure pump 2 as a low-pressure pump, and thus is supplied to the high-pressure pump 5 even when the diesel engine 40 is stopped.
  • the flow rate of low-pressure fuel can be secured. Therefore, in any of the pressure-accumulation fuel injection devices in FIGS. 3 to 6, the crankshaft 43 can be advanced or retracted when the crank angle Ca is shifted.
  • control mode 2 Control when the rail pressure is maintained above the injectable pressure (control mode 2)
  • the position is related to the position of the plunger 7 of the high-pressure pump 5.
  • the crank angle Ca is shifted so that the compression stroke required according to the characteristics of the diesel engine 40 is performed before fuel injection. In this case, since the normal injection of the high-pressure fuel is already possible, the fuel is injected after the compression stroke for a predetermined stroke is performed, and the diesel engine 40 is restarted promptly.
  • the intake stroke, the compression stroke, the explosion stroke, and the exhaust stroke are repeated in each cylinder, and fuel injection is performed in the compression stroke.
  • the rail pressure Pr is equal to or higher than the injectable pressure Pr0, and when normal injection of high-pressure fuel is possible, the cylinder at which the next fuel injection timing comes is detected,
  • the target position Catgt of the crank angle Ca is set so that cranking starts from the crank angle Ca at which a compression stroke for a predetermined stroke is performed.
  • the required compression stroke before fuel injection is obtained in advance for each diesel engine 40 by a test or the like.
  • FIG. 7 shows the relationship between the piston lift position and the crank angle Ca of the diesel engine 40 in one cylinder.
  • the fuel injection timing is set at a time when the crank angle Ca is 710 °, which is close to the end of the compression stroke. If the required compression stroke before fuel injection obtained in advance by testing or the like is, for example, a displacement of the crank angle Ca by 100 °, the target position Catgt for shifting the crank angle Ca is set to 610 °. If it is better to include a slight intake stroke, the target position Catgt for shifting the crank angle Ca is set to 520 °, for example, and cranking is started from the intake stroke. As a result, since the fuel is injected into the cylinder 41 after a necessary stroke after the start of cranking, the diesel engine 40 is quickly restarted.
  • step S1 the rotational speed Ne of the diesel engine 40, the accelerator pedal operation amount Acc, the brake pedal operation amount Brk, the transmission clutch position Cp, and the transmission shift position Gp are determined. Read.
  • step S2 it is determined whether or not a preset idling stop condition is satisfied based on the information such as the sensor value read in step S1. Steps S1 and S2 are repeated until the idling stop condition is satisfied.
  • step S3 When the idling stop condition is satisfied, the fuel injection is stopped and the diesel engine 40 is stopped in step S3, and the crank angle Ca when the diesel engine 40 is stopped is detected and stored in step S4. Furthermore, in step S5, based on the information stored in the control device 70, the cylinder (fuel injection valve) from which the fuel injection timing comes next is detected.
  • step S6 the rail pressure Pr is detected, and it is further determined whether or not the rail pressure Pr detected in step S7 is less than the injectable pressure Pr0.
  • step S7 when the rail pressure Pr becomes less than the injectable pressure Pr0, the process proceeds to step S8 in which the crank angle shift control in the control mode 1 is performed.
  • step S14 when the rail pressure Pr is equal to or higher than the injectable pressure Pr0, The process proceeds to step S14 where the crank angle shift control in the control mode 2 is performed.
  • step S9 the crank angle Ca when the diesel engine 40 is stopped detected in step S4, and the next fuel injection timing detected in step S5.
  • the target position Catgt for shifting the crank angle Ca is set on the basis of the information on the cylinder in which the air pressure arrives and the displacement of the crank angle Ca necessary to enable normal injection of high-pressure fuel for each cylinder stored in advance.
  • step S10 in accordance with the target position Catgt set in step S9, an instruction is output to the starter 44, and the rail pressure Pr quickly reaches the injectable pressure Pr0 or more after the diesel engine 40 is restarted.
  • the crank angle Ca is shifted.
  • step S11 the accelerator pedal operation amount Acc, the brake pedal operation amount Brk, the transmission clutch position Cp, the transmission shift position Gp, etc. are read, and at step S12. It is determined whether or not an engine restart condition is satisfied. Steps S11 to S12 are repeated until the engine restart condition is satisfied. When the engine restart condition is satisfied, the process proceeds to step S13, cranking of the diesel engine 40 is started, and the diesel engine 40 is quickly started. To do. Note that step S10 for shifting the crank angle Ca may be performed after step S12 when the engine restart condition is satisfied.
  • step S6 when the rail pressure Pr is equal to or higher than the injectable pressure Pr0 in step S6, the process proceeds to step S14 where the crank angle shift control in the control mode 2 is performed.
  • step S15 the accelerator pedal operation amount Acc and the brake pedal operation The amount Brk, the transmission clutch position Cp, the transmission shift position Gp, and the like are read, and it is determined in step S16 whether or not an engine restart condition is satisfied. If the engine restart condition is not satisfied, the process returns to step S6, and the same steps as before are performed.
  • step S16 If the engine restart condition is satisfied in step S16, the rail pressure Pr is maintained at or above the injectable pressure Pr0 until the engine restart condition is satisfied.
  • the target position Catgt is set at a position stored in advance so that cranking is restarted from the crank angle Ca at which the necessary compression stroke is ensured before fuel injection. Is set.
  • step S18 an instruction is output to the starter 44 in accordance with the target position Catgt set in step S17, and the crank angle Ca is shifted.
  • step S13 cranking of the diesel engine 40 is started, and the diesel engine 40 is started quickly. Note that steps S17 to S18 may be performed in advance before performing step S16 for determining whether or not the engine restart condition is satisfied.
  • the crank angle Ca is shifted to a predetermined position set in advance. It is like that.
  • the control device 70 is configured to be able to calculate the required number of pumping times by the high-pressure pump 5 from the difference between the rail pressure Pr and the injectable pressure Pr0 when the diesel engine 40 is restarted, the diesel engine by idling stop control
  • the rail pressure Pr is detected and the required number of pumping times of the high pressure pump 5 is calculated, and the target position for shifting the crank angle is determined according to the required number of pumping times, Crank angle shifting control may be performed.
  • the second embodiment of the present invention is an example in the case where a pump that depends on the rotational state of a diesel engine such as a gear pump is used as a low-pressure pump provided in an accumulator fuel injection device.
  • the low-pressure pump is a gear pump
  • the gear pump is connected to the crankshaft of the diesel engine. Therefore, the driving force of the low-pressure pump depends on the rotational state of the diesel engine, and low-pressure fuel is not supplied to the pressurizing chamber of the high-pressure pump when the diesel engine is stopped.
  • the crankshaft is retreated to shift the crank angle before starting the diesel engine, fuel is not supplied to the pressurizing chamber regardless of the vertical movement of the plunger of the high-pressure pump.
  • crank angle control unit of the control device of the present embodiment causes the rail pressure to reach the pressure at which normal injection of high-pressure fuel can be performed when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped.
  • control is performed to shift the crank angle with the high-pressure pump in the fuel intake stroke as a target position.
  • the control device of the present embodiment when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine is stopped by the idling stop control, the control device of the present embodiment also has a rail pressure at the time of restart.
  • the crank angle Ca is shifted so that Pr quickly reaches the injectable pressure Pr0 or more (control mode 1).
  • the control device of the present embodiment is a position where the compression stroke necessary for fuel injection is performed at the time of restart when the rail pressure Pr is maintained at the injectable pressure Pr0 or higher even when the diesel engine is stopped.
  • the crank angle Ca is shifted so that cranking starts from (control mode 2).
  • control mode 2 performed when the rail pressure Pr is maintained at the injectable pressure Pr0 or higher even when the diesel engine is stopped is the same as the content described in the first embodiment.
  • control mode 1 performed when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine is stopped by the idling stop control is different from the first embodiment. explain.
  • FIG. 9 is a diagram for explaining a crank angle adjustment method executed when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine is stopped, and is described in the first embodiment.
  • FIG. 4 is a diagram corresponding to FIG. 3.
  • the accumulator fuel injection that requires a maximum of 1.5 pumping cycles from the high pressure pump until the rail pressure Pr is changed from the atmospheric pressure to the injectable pressure Pr0 or more. It is an example of an apparatus.
  • a stroke in which the lift position of the plunger is increased represents a fuel pressure feed stroke
  • a stroke in which the lift amount of the plunger is decreased represents a fuel intake stroke.
  • the low pressure pump is a pump that depends on the rotational state of the diesel engine
  • the low pressure fuel is not supplied to the pressurizing chamber of the high pressure pump while the diesel engine is stopped. Therefore, even if the target position Catgt of the crank angle Ca is set during the fuel pumping stroke of the high-pressure pump so that the fuel pumping stroke of the required number of pumping times from the high-pressure pump is simply performed, the high-pressure fuel pumping to the common rail is performed. The amount may not be secured.
  • crank angle Ca is shifted with the state where the high-pressure pump is in the fuel intake stroke as the target position. Since the target position Catgt of the crank angle Ca is set so that the required number of fuel intake strokes from the start of cranking to the fuel injection timing are performed, the forward / backward direction when shifting the crank angle Ca may be either. In the example of FIG.
  • the fuel intake stroke is secured 1.5 times from the cranking start time to the fuel injection timing.
  • the target position Catgt for shifting the crank angle Ca is set to 225 °.
  • the diesel engine is stopped at a position where the crank angle Ca is 450 ° by the idling stop control.
  • the crank angle Ca It is necessary to set the target position Catgt to 225 ° and shift the crank angle Ca by ⁇ 225 °.
  • the crank angle Ca It is necessary to set the target position Catgt to 405 ° and shift the crank angle Ca by ⁇ 45 °.
  • crank angle Ca it is necessary to set the target position Catgt of crank angle Ca to 585 ° and shift crank angle Ca by + 135 °, and if it is desired to start fuel injection from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 765 ° and shift the crank angle Ca by + 315 °.
  • the amount of shift of the crank angle Ca is minimized when fuel injection is started from the cylinder # 1, so the target position Catgt (A) of the crank angle Ca is set to 405 °, and the diesel engine The crank angle Ca is shifted by the time of restart.
  • the time to shift the crank angle Ca is minimized, the load to shift the crank angle Ca is reduced, and normal injection of high-pressure fuel is possible in a short time after cranking is started when the diesel engine is restarted become.
  • the displacement of the crank angle Ca required to secure the fuel intake stroke for the maximum number of pumping times of the high-pressure pump 5 that enables normal injection of high-pressure fuel at each fuel injection timing is the fuel injection timing or It differs depending on the required maximum number of pumping times of the high-pressure pump 5. Therefore, the target position Catgt is set so that the amount by which the crank angle Ca is shifted is minimized based on the crank angle Ca when the diesel engine is stopped and the cranking start position at which the required number of fuel intake strokes are secured. As a result, the crank angle Ca is shifted.
  • the amount of shifting the crank angle Ca to the target position Catgt is small, and the load on the battery and starter is reduced.
  • the time for shifting the crank angle Ca can be shortened, so that the diesel engine can be restarted quickly.
  • the engine restart condition is satisfied when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped by the idling stop control.
  • the crank angle is shifted so that the rail pressure quickly reaches the injectable pressure when cranking is started.
  • cranking is started from the position where the necessary compression stroke is performed before fuel injection.
  • the crank angle is shifted as shown. Therefore, the diesel engine can be restarted promptly according to the rail pressure state when the engine restart condition is satisfied.

Abstract

Provided is a control apparatus for a diesel engine, by which the diesel engine can be restarted within a short space of time when the diesel engine which has been stopped under an idle-stop control is to be restarted. The control apparatus for controlling a diesel engine having a pressure accumulation type fuel injection device is provided with an idle stop control unit which stops the diesel engine when a predetermined idle stop condition is satisfied and which restarts the diesel engine when a predetermined restart condition is satisfied, and a crank angle control unit which performs a control to shift the crank angle of the diesel engine during the stoppage of the diesel engine so that the pressure in a common rail can quickly reach a pressure at which the normal injection of a high-pressure fuel can be performed when the diesel engine is restarted.

Description

ディーゼルエンジンの制御装置Diesel engine control device
　本発明は、ディーゼルエンジンの制御装置に関し、特に、アイドリングストップ制御が可能なディーゼルエンジンの制御に用いられるディーゼルエンジンの制御装置に関する。 The present invention relates to a control device for a diesel engine, and more particularly, to a control device for a diesel engine used for controlling a diesel engine capable of idling stop control.
　従来、複数の燃料噴射弁が接続されるとともに高圧燃料が蓄積されるコモンレールを備え、高圧ポンプで加圧された高圧燃料が各燃料噴射弁に供給された状態で燃料噴射弁の通電制御を行うことによって、燃料の緻密な噴射制御を可能にした蓄圧式燃料噴射装置を備えた内燃機関がある。 Conventionally, a plurality of fuel injection valves are connected and a common rail for storing high-pressure fuel is provided, and energization control of the fuel injection valves is performed in a state where high-pressure fuel pressurized by a high-pressure pump is supplied to each fuel injection valve Thus, there is an internal combustion engine equipped with an accumulator fuel injection device that enables precise fuel injection control.
　ここで、主として車両に搭載される内燃機関には、燃費の改善や排気ガスの低減を目的として、内燃機関のアイドル時に内燃機関を停止させるアイドリングストップ制御が可能に構成されたものがある。このアイドリングストップ制御では、内燃機関の停止時において所定のアイドリングストップ条件が成立した時に内燃機関を停止させるとともに、所定の再始動条件が成立した時に内燃機関を再始動させる制御が行われる。 Here, some internal combustion engines mounted mainly on vehicles are configured to be capable of idling stop control for stopping the internal combustion engine when the internal combustion engine is idle for the purpose of improving fuel consumption and reducing exhaust gas. In the idling stop control, the internal combustion engine is stopped when a predetermined idling stop condition is satisfied when the internal combustion engine is stopped, and the internal combustion engine is restarted when a predetermined restart condition is satisfied.
　このようなアイドリングストップ制御が可能な内燃機関において、内燃機関が停止するまでに要する時間を短縮させたり再始動性を向上させたりすることができる内燃機関の制御装置が提案されている。具体的には、アイドリングストップ制御による内燃機関の停止時に高圧ポンプの吐出流量を増加させ内燃機関の負荷を調節することで、クランク角を再始動に適した所定のクランク角で停止させ、再始動時にはスタータの作動と同時に燃料噴射を開始させる内燃機関の制御装置が開示されている（特許文献１参照）。 In such an internal combustion engine capable of idling stop control, a control device for an internal combustion engine has been proposed that can shorten the time required for the internal combustion engine to stop and improve the restartability. Specifically, when the internal combustion engine is stopped by idling stop control, the discharge flow rate of the high-pressure pump is increased and the load on the internal combustion engine is adjusted to stop the crank angle at a predetermined crank angle suitable for restarting. A control device for an internal combustion engine that sometimes starts fuel injection simultaneously with the starter operation is disclosed (see Patent Document 1).
特開２００８－１６３７９６号公報　（全文、全図）JP 2008-163796 A (full text, full diagram)
　ところで、蓄圧式燃料噴射装置を備えた内燃機関、特にディーゼルエンジンにおいては、始動の条件として、気筒内の圧縮が十分であること、及び、蓄圧式燃料噴射装置のコモンレール内の圧力（以下「レール圧」と称する。）が十分に高い状態となっていて液垂れ等のない高圧燃料の正常な噴射が可能であることの二つの大きな条件がある。 By the way, in an internal combustion engine equipped with an accumulator fuel injection device, particularly a diesel engine, as a starting condition, the compression in the cylinder is sufficient, and the pressure in the common rail of the accumulator fuel injector (hereinafter referred to as “rail”). There are two major conditions that the high pressure fuel can be normally injected without dripping or the like.
　気筒内が十分に圧縮されていない状態では、燃料が気筒内に噴射されても爆発が生じ得ない。気筒内が十分に圧縮された状態となるためには、およそ９０～１５０°分のクランク角の変位が必要とされる。一方、特許文献１の内燃機関の制御装置のように、内燃機関の停止時にクランク角を所定のクランク角で停止させた場合であっても、内燃機関がコモンレールを備えたディーゼルエンジンである場合、レール圧が十分に上昇していない間はエンジンの再始動時にスタータの作動と同時に燃料噴射弁の制御を開始しても高圧燃料の正常噴射が行われないため、気筒内で爆発が生じ得ない。 In a state where the inside of the cylinder is not sufficiently compressed, even if fuel is injected into the cylinder, no explosion can occur. In order for the inside of the cylinder to be sufficiently compressed, a crank angle displacement of approximately 90 to 150 ° is required. On the other hand, even when the crank angle is stopped at a predetermined crank angle when the internal combustion engine is stopped, as in the control device for the internal combustion engine of Patent Document 1, when the internal combustion engine is a diesel engine having a common rail, As long as the rail pressure is not sufficiently high, even if the starter is activated and the control of the fuel injection valve is started at the same time as restarting the engine, normal injection of high-pressure fuel is not performed, so no explosion can occur in the cylinder. .
　蓄圧式燃料噴射装置に用いられる燃料噴射弁には、主に電磁ソレノイドを備えたマグネットインジェクタやピエゾ素子を備えたピエゾインジェクタがある。これらの燃料噴射弁において、その構造上、噴射孔を開閉するノズルニードルの後端側に負荷された背圧を逃がすための背圧逃がし通路以外に、低圧燃料を燃料タンクに戻すためのリーク通路が設けられる場合がある。 2. Description of the Related Art Fuel injection valves used for pressure accumulating fuel injection devices include a magnet injector mainly equipped with an electromagnetic solenoid and a piezo injector equipped with a piezo element. In these fuel injection valves, a leak passage for returning low-pressure fuel to the fuel tank in addition to a back pressure relief passage for releasing the back pressure loaded on the rear end side of the nozzle needle that opens and closes the injection hole due to its structure May be provided.
　具体的には、コモンレールから燃料噴射弁に供給される高圧燃料は、ノズルニードルの先端側の噴射孔に送られるとともに、ノズルニードルに背圧を付加するために背圧室に送られる。このうち、噴射孔側に送られる高圧燃料の一部は、噴射孔から噴射される以外に、ノズルニードルの周囲を通って燃料噴射弁内の低圧側にリークする。このリークした燃料はその圧力差によって他の高圧側に移動することができなくなることから、燃料噴射弁にリーク通路を設けることで、リークした燃料を燃料噴射弁から燃料タンクに戻すように構成されている。 Specifically, the high-pressure fuel supplied from the common rail to the fuel injection valve is sent to the injection hole on the tip side of the nozzle needle and is sent to the back pressure chamber in order to apply a back pressure to the nozzle needle. Among these, a part of the high-pressure fuel sent to the injection hole side leaks to the low-pressure side in the fuel injection valve through the periphery of the nozzle needle, in addition to being injected from the injection hole. Since the leaked fuel cannot move to another high pressure side due to the pressure difference, a leak passage is provided in the fuel injection valve so that the leaked fuel is returned from the fuel injection valve to the fuel tank. ing.
　一方、背圧逃がし通路以外の部分から、高圧燃料が低圧側にリークすることがない構造の燃料噴射弁においては、基本的にはディーゼルエンジンの停止直後からレール圧が低下することがなく、いつでも燃料噴射が可能な状態となっている。ただし、このような燃料噴射弁においても、燃料噴射弁やコモンレールに接続される圧力制御弁等の劣化等によって高圧燃料が漏れやすくなり、ディーゼルエンジンの停止直後からレール圧が低下しやすくなるおそれがある。 On the other hand, in a fuel injection valve with a structure in which high-pressure fuel does not leak to the low-pressure side from parts other than the back pressure relief passage, the rail pressure does not decrease immediately after the diesel engine is stopped. Fuel injection is possible. However, even in such a fuel injection valve, high pressure fuel tends to leak due to deterioration of the fuel injection valve, a pressure control valve connected to the common rail, etc., and the rail pressure may easily decrease immediately after the diesel engine stops. is there.
　アイドリングストップ制御によってディーゼルエンジンが停止した後にレール圧が低下してしまうと、クランク角によっては、ディーゼルエンジンを再始動させる際にクランキングを開始してから高圧燃料の正常噴射が可能な圧力（以下「噴射可能圧力」と称する。）にレール圧が戻るまでに時間を要してしまう。すなわち、特許文献１の内燃機関の制御装置のようにクランク角の調整が行われ、再始動条件が成立したときにクランク角が再始動に適した所定位置にあったとしても、高圧燃料の正常噴射が可能な圧力以上にレール圧が上昇するまでに時間を要し、ディーゼルエンジンが再始動するまでに時間がかかってしまう。 If the rail pressure drops after the diesel engine stops due to idling stop control, depending on the crank angle, the pressure that allows normal injection of high-pressure fuel after cranking starts when the diesel engine is restarted (below) It takes time until the rail pressure returns to “injectable pressure”. That is, even if the crank angle is adjusted as in the control device of the internal combustion engine of Patent Document 1 and the restart condition is satisfied, the normal pressure of the high-pressure fuel is normal even if the crank angle is at a predetermined position suitable for restart. It takes time for the rail pressure to rise above the pressure at which injection is possible, and it takes time for the diesel engine to restart.
　そこで、本発明の発明者は鋭意努力し、アイドリングストップ制御が可能なディーゼルエンジンの制御装置において、アイドリングストップ制御によるディーゼルエンジンの停止中に、再始動時にレール圧が高圧燃料の正常噴射が可能な圧力以上に速やかに到達するようにディーゼルエンジンのクランク角をずらすよう制御を行うことにより上述した問題を解決できることを見出し、本発明を完成させたものである。すなわち、本発明は、アイドリングストップ制御によるディーゼルエンジンの停止後の再始動時に、ディーゼルエンジンを短時間で再始動可能にするディーゼルエンジンの制御装置を提供することを目的とする。 Accordingly, the inventors of the present invention have made diligent efforts and in a diesel engine control device capable of idling stop control, during the restart of the diesel engine by idling stop control, rail pressure allows normal injection of high-pressure fuel at restart. The present invention has been completed by finding that the above-mentioned problems can be solved by performing control to shift the crank angle of the diesel engine so as to reach the pressure more quickly than the pressure. That is, an object of the present invention is to provide a diesel engine control device that enables a diesel engine to be restarted in a short time when the diesel engine is restarted after being stopped by idling stop control.
　本発明によれば、ディーゼルエンジンの駆動に伴って駆動される高圧ポンプと、高圧ポンプで加圧された燃料が蓄積されるコモンレールと、コモンレールに接続され燃料をディーゼルエンジンの気筒内に噴射する複数の燃料噴射弁と、を有する蓄圧式燃料噴射装置を備えたディーゼルエンジンの制御を行うためのディーゼルエンジンの制御装置において、所定のアイドリングストップ条件が成立したときにディーゼルエンジンを停止させるとともに、所定の再始動条件が成立したときにディーゼルエンジンを再始動させる制御を行うアイドリングストップ制御部と、ディーゼルエンジンの停止中に、ディーゼルエンジンの再始動時にコモンレール内の圧力が高圧燃料の正常噴射が可能な圧力以上に速やかに到達するようにディーゼルエンジンのクランク角をずらす制御を行うクランク角制御部と、を備えることを特徴とするディーゼルエンジンの制御装置が提供され、上述した問題を解決することができる。 According to the present invention, a high-pressure pump that is driven as the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and a plurality that is connected to the common rail and injects fuel into the cylinder of the diesel engine. And a diesel engine control device for controlling a diesel engine equipped with a pressure-accumulation fuel injection device having a fuel injection valve, and stopping a diesel engine when a predetermined idling stop condition is satisfied, An idling stop control unit that controls to restart the diesel engine when the restart condition is satisfied, and a pressure at which the pressure in the common rail can normally inject high-pressure fuel when the diesel engine is restarted while the diesel engine is stopped Diesel engine to reach more quickly Of the crank angle control unit for controlling shifting of the crank angle, it is provided control apparatus for a diesel engine comprising: a, it is possible to solve the problems described above.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、クランク角制御部は、コモンレール内の圧力を高圧燃料の正常噴射が可能な圧力以上にするために必要な高圧ポンプの最大圧送回数に応じて、クランク角をずらす目標位置を決定することが好ましい。 Further, when configuring the control device for the diesel engine of the present invention, the crank angle control unit responds to the maximum number of pumping of the high-pressure pump necessary to make the pressure in the common rail equal to or higher than the pressure at which high-pressure fuel can be normally injected. Thus, it is preferable to determine a target position for shifting the crank angle.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、クランク角制御部は、再始動時の燃料噴射タイミングでの高圧ポンプのプランジャのリフト位置に応じて、クランク角をずらす目標位置を決定することが好ましい。 Further, when configuring the diesel engine control device of the present invention, the crank angle control unit determines a target position to shift the crank angle according to the lift position of the plunger of the high-pressure pump at the fuel injection timing at the time of restart. It is preferable.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、クランク角制御部は、ディーゼルエンジンの再始動時に燃料噴射弁からの高圧燃料の正常噴射が可能となる目標位置を複数の燃料噴射弁ごとにそれぞれ演算するとともに、それぞれ算出された複数の目標位置のうち、クランク角をずらす量が最小となる目標位置にクランク角をずらすことが好ましい。 Further, in configuring the diesel engine control device of the present invention, the crank angle control unit sets the target position at which normal injection of high-pressure fuel from the fuel injection valve is possible when the diesel engine is restarted for each of the plurality of fuel injection valves. Preferably, the crank angle is shifted to a target position that minimizes the amount of shift of the crank angle among the plurality of calculated target positions.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、高圧ポンプに燃料を供給する低圧ポンプがディーゼルエンジンの回転状態に依存せずに駆動されるポンプである場合には、クランク角制御部は高圧ポンプが燃料圧送行程にある状態を目標位置としてクランク角を進角又は退角させる制御を選択的に行うことが好ましい。 Further, when configuring the diesel engine control device of the present invention, when the low pressure pump that supplies fuel to the high pressure pump is a pump that is driven without depending on the rotational state of the diesel engine, the crank angle control unit is It is preferable to selectively perform control for advancing or retreating the crank angle with the state where the high pressure pump is in the fuel pressure stroke as the target position.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、高圧ポンプに燃料を供給する低圧ポンプがディーゼルエンジンの回転状態に依存して駆動されるポンプである場合には、クランク角制御部は高圧ポンプの最大圧送回数が確保されるように高圧ポンプが燃料吸入行程にある状態を目標位置としてクランク角を進角又は退角させる制御を行うことが好ましい。 In configuring the diesel engine control device of the present invention, when the low-pressure pump that supplies fuel to the high-pressure pump is a pump driven depending on the rotational state of the diesel engine, the crank angle control unit It is preferable to perform control to advance or retract the crank angle with the target position being the state where the high-pressure pump is in the fuel intake stroke so that the maximum number of pumping times of the pump is ensured.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、ディーゼルエンジンの制御装置は、コモンレール内の圧力を検出するレール圧検出部を備え、クランク角制御部は、再始動条件成立時に検出されるコモンレール内の圧力と、高圧燃料の正常噴射が可能な圧力との差に基づき、クランク角をずらす目標位置を決定することが好ましい。 In configuring the diesel engine control device of the present invention, the diesel engine control device includes a rail pressure detection unit that detects the pressure in the common rail, and the crank angle control unit is detected when the restart condition is satisfied. The target position for shifting the crank angle is preferably determined based on the difference between the pressure in the common rail and the pressure at which normal injection of high-pressure fuel is possible.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、ディーゼルエンジンの制御装置は、コモンレール内の圧力を検出するレール圧検出部を備え、クランク角制御部は、ディーゼルエンジンの停止中にコモンレール内の圧力が高圧燃料の正常噴射が可能な圧力未満になったとき、クランク角をずらす制御を行うことが好ましい。 In configuring the diesel engine control device of the present invention, the diesel engine control device includes a rail pressure detection unit that detects the pressure in the common rail, and the crank angle control unit is installed in the common rail while the diesel engine is stopped. It is preferable to perform control to shift the crank angle when the pressure becomes less than a pressure at which high pressure fuel can be normally injected.
　また、本発明のディーゼルエンジンの制御装置を構成するにあたり、クランク角制御部は、再始動条件成立時におけるコモンレール内の圧力が高圧燃料の正常噴射が可能な圧力以上のときには、ディーゼルエンジンが圧縮行程から始まるようにクランク角をずらす制御を行うことが好ましい。 Further, in configuring the control device for the diesel engine of the present invention, the crank angle control unit is configured so that the diesel engine performs the compression stroke when the pressure in the common rail when the restart condition is satisfied is equal to or higher than the pressure at which high pressure fuel can be normally injected. It is preferable to perform control to shift the crank angle so as to start from.
　本発明のディーゼルエンジンの制御装置によれば、アイドリングストップ制御によるディーゼルエンジンの停止中に、再始動時にディーゼルエンジンがクランキングされたときにレール圧が噴射可能圧力以上に速やかに到達するようにディーゼルエンジンのクランク角がずらされる。そのため、高圧ポンプのプランジャのリフト位置が、レール圧が噴射可能圧力以上に速やかに到達するような位置におかれた状態でディーゼルエンジンが再始動される。したがって、再始動条件の成立後速やかに高圧燃料の正常噴射が可能となり、ディーゼルエンジンが再始動するまでの時間が短縮される。 According to the control apparatus for a diesel engine of the present invention, the diesel engine is set so that the rail pressure quickly reaches the injectable pressure when the diesel engine is cranked during the restart while the diesel engine is stopped by the idling stop control. The crank angle of the engine is shifted. Therefore, the diesel engine is restarted in a state where the lift position of the plunger of the high-pressure pump is at a position where the rail pressure quickly reaches the injectable pressure or more. Therefore, normal injection of high-pressure fuel becomes possible immediately after the restart condition is satisfied, and the time until the diesel engine is restarted is shortened.
　また、本発明のディーゼルエンジンの制御装置において、レール圧を噴射可能圧力以上にするために必要な高圧ポンプの最大圧送回数（以下「必要最大圧送回数」と称する。）に応じてクランク角をずらす目標位置を決定することにすれば、必要最大圧送回数に応じて速やかに気筒内への高圧燃料の正常噴射が可能になる。 Further, in the control device for a diesel engine of the present invention, the crank angle is shifted in accordance with the maximum number of pumping times of the high-pressure pump necessary for making the rail pressure equal to or higher than the injectable pressure (hereinafter referred to as “required maximum pumping frequency”). If the target position is determined, normal injection of high-pressure fuel into the cylinder can be promptly performed according to the required maximum number of pumping times.
　また、本発明のディーゼルエンジンの制御装置において、再始動時の燃料噴射タイミングでの高圧ポンプのプランジャのリフト位置に応じてクランク角をずらす目標位置が決定されるようにすれば、燃料噴射タイミングと高圧ポンプのプランジャのリフト位置との関係に応じて速やかに気筒内への高圧燃料の正常噴射が可能になる。 Further, in the control device for a diesel engine of the present invention, if the target position for shifting the crank angle is determined according to the lift position of the plunger of the high-pressure pump at the fuel injection timing at restart, the fuel injection timing and Normal injection of high-pressure fuel into the cylinder can be quickly performed in accordance with the relationship with the lift position of the plunger of the high-pressure pump.
　また、本発明のディーゼルエンジンの制御装置において、複数の燃料噴射弁ごとにクランク角の目標位置を演算するとともに、クランク角をずらす量が最小となる目標位置にクランク角をずらすことにより、クランク角をずらすための時間を最も短くすることができ、クランク角をずらすための負荷が小さくなる。 Further, in the control device for a diesel engine according to the present invention, the crank angle target position is calculated for each of the plurality of fuel injection valves, and the crank angle is shifted to the target position where the amount of shifting the crank angle is minimized. The time for shifting the crank angle can be shortened, and the load for shifting the crank angle is reduced.
　また、本発明のディーゼルエンジンの制御装置において、低圧ポンプがディーゼルエンジンの回転状態に依存せずに駆動されるポンプである場合に高圧ポンプが燃料圧送行程にある状態を目標位置としてクランク角を進角又は退角させる制御が行われることで、クランク角をずらす量を最小にすることができる。すなわち、低圧ポンプがディーゼルエンジンの回転状態に依存せずに駆動されるポンプである場合には、ディーゼルエンジンの始動前でも低圧ポンプを作動させて高圧ポンプの加圧室に確実に燃料を供給することができることから、クランク角を自由に進角又は退角させることができる。 In the diesel engine control apparatus of the present invention, when the low-pressure pump is a pump driven without depending on the rotational state of the diesel engine, the crank angle is advanced with the target position being the state where the high-pressure pump is in the fuel pressure stroke. The amount of shifting the crank angle can be minimized by controlling the angle or retraction. That is, when the low-pressure pump is driven without depending on the rotational state of the diesel engine, the fuel is reliably supplied to the pressurizing chamber of the high-pressure pump by operating the low-pressure pump even before starting the diesel engine. Therefore, the crank angle can be freely advanced or retracted.
　また、本発明のディーゼルエンジンの制御装置において、低圧ポンプがディーゼルエンジンの回転状態に依存して駆動されるポンプである場合には、高圧ポンプの最大圧送回数が確保されるように高圧ポンプが燃料吸入行程にある状態を目標位置としてクランク角を進角又は退角させる制御が行われることで、クランク角をずらす量をできる限り小さくしつつ、レール圧が噴射可能圧力以上に速やかに到達するような位置へクランク角を確実にずらすことができる。すなわち、低圧ポンプがディーゼルエンジンの回転状態に依存して駆動されるポンプである場合には、クランク角を後退させても燃料が加圧室に供給されることがないため、高圧ポンプの圧送回数が確実に最大圧送回数分確保されるような目標位置が優先的に選択されてクランク角がずらされる。 In the diesel engine control apparatus of the present invention, when the low-pressure pump is a pump driven depending on the rotational state of the diesel engine, the high-pressure pump is fueled to ensure the maximum number of pumping times of the high-pressure pump. By controlling the crank angle to be advanced or retreated with the state in the intake stroke as the target position, the rail pressure reaches the injection possible pressure more quickly while minimizing the amount of shift of the crank angle. The crank angle can be shifted to the correct position. That is, when the low-pressure pump is a pump driven depending on the rotational state of the diesel engine, the fuel is not supplied to the pressurizing chamber even if the crank angle is retracted. However, the target position that ensures the maximum number of pumping times is preferentially selected and the crank angle is shifted.
　また、本発明のディーゼルエンジンの制御装置において、再始動条件成立時のレール圧と噴射可能圧力との差に基づきクランク角をずらす目標位置を決定すれば、レール圧が噴射可能圧力以上になるための高圧ポンプの必要圧送回数に応じてクランク角がずらされるため、必要最大圧送回数未満でレール圧が噴射可能圧力以上になり、速やかに気筒内への燃料噴射が可能になる。 In the diesel engine control device of the present invention, if the target position for shifting the crank angle is determined based on the difference between the rail pressure when the restart condition is established and the injectable pressure, the rail pressure becomes equal to or higher than the injectable pressure. Since the crank angle is shifted according to the required number of pumping times of the high-pressure pump, the rail pressure becomes equal to or higher than the injectable pressure below the required maximum number of pumping times, and the fuel can be quickly injected into the cylinder.
　また、本発明のディーゼルエンジンの制御装置において、ディーゼルエンジンの停止中にレール圧が噴射可能圧力未満になったときにクランク角をずらす制御が行われることで、レール圧が充分に確保されている状態ではレール圧を噴射可能圧力以上に速やかに到達させるためのクランク角をずらす制御を行う必要がなくなる。 Further, in the control device for a diesel engine according to the present invention, when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped, the control for shifting the crank angle is performed, so that the rail pressure is sufficiently secured. In this state, it is not necessary to perform control for shifting the crank angle in order to make the rail pressure reach more quickly than the injectable pressure.
　また、本発明のディーゼルエンジンの制御装置において、再始動条件成立時のレール圧が所定値を超えるときには、ディーゼルエンジンが圧縮行程から始まるようにディーゼルエンジンのクランク角がずらされる。したがって、レール圧が充分に確保されている状態では、再始動条件の成立後、速やかにディーゼルエンジンの気筒内に燃料が噴射されるとともに気筒内で爆発が生じ、ディーゼルエンジンのより速やかな始動が可能になる。 In the diesel engine control device of the present invention, when the rail pressure when the restart condition is satisfied exceeds a predetermined value, the crank angle of the diesel engine is shifted so that the diesel engine starts from the compression stroke. Therefore, in a state where the rail pressure is sufficiently secured, after the restart condition is established, the fuel is quickly injected into the cylinder of the diesel engine and an explosion occurs in the cylinder, so that the diesel engine can be started more quickly. It becomes possible.
ディーゼルエンジンの蓄圧式燃料噴射装置の構成例を示す図である。It is a figure which shows the structural example of the pressure accumulation type fuel-injection apparatus of a diesel engine. 本発明の第１の実施の形態にかかるディーゼルエンジンの制御装置の構成例を示す図である。It is a figure which shows the structural example of the control apparatus of the diesel engine concerning the 1st Embodiment of this invention. 第１の実施の形態にかかるディーゼルエンジンの停止中にレール圧が低下した場合のクランク角ずらし制御について説明するための図である。It is a figure for demonstrating crank angle shift control in case rail pressure falls during the stop of the diesel engine concerning 1st Embodiment. 第１の実施の形態にかかるディーゼルエンジンの停止中にレール圧が低下した場合のクランク角ずらし制御について説明するための図である。It is a figure for demonstrating crank angle shift control in case rail pressure falls during the stop of the diesel engine concerning 1st Embodiment. 第１の実施の形態にかかるディーゼルエンジンの停止中にレール圧が低下した場合のクランク角ずらし制御について説明するための図である。It is a figure for demonstrating crank angle shift control in case rail pressure falls during the stop of the diesel engine concerning 1st Embodiment. 第１の実施の形態にかかるディーゼルエンジンの停止中にレール圧が低下した場合のクランク角ずらし制御について説明するための図である。It is a figure for demonstrating crank angle shift control in case rail pressure falls during the stop of the diesel engine concerning 1st Embodiment. エンジン再始動条件成立時までレール圧が維持されていた場合のクランク角ずらし制御について説明するための図である。It is a figure for demonstrating crank angle shift control in case rail pressure is maintained until engine restart conditions are satisfied. ディーゼルエンジンの制御方法の一例を示す制御フロー図である。It is a control flowchart which shows an example of the control method of a diesel engine. 第２の実施の形態にかかるディーゼルエンジンの停止中にレール圧が低下した場合のクランク角ずらし制御について説明するための図である。It is a figure for demonstrating crank angle shift control in case rail pressure falls during the stop of the diesel engine concerning 2nd Embodiment.
　以下、図面を参照して、本発明のディーゼルエンジンの制御装置に関する実施の形態について具体的に説明する。ただし、以下の実施の形態は本発明の一態様を示すものであり、この発明を限定するものではなく、本発明の範囲内で任意に変更することが可能である。なお、それぞれの図中、同じ符号を付してあるものは同一の部材を示しており、適宜説明が省略されている。 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments relating to a diesel engine control device of the present invention will be specifically described below with reference to the drawings. However, the following embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention. In addition, what attached | subjected the same code | symbol in each figure has shown the same member, and description is abbreviate | omitted suitably.
［第１の実施の形態］
１．ディーゼルエンジン及び蓄圧式燃料噴射装置の基本的構成
　図１は、本発明の実施の形態にかかるディーゼルエンジン４０の制御装置７０によって制御が行われるディーゼルエンジン４０、及び、ディーゼルエンジン４０に備えられた蓄圧式燃料噴射装置５０の概略構成を示している。 [First Embodiment]
1. FIG. 1 shows a diesel engine 40 that is controlled by the control device 70 of the diesel engine 40 according to an embodiment of the present invention, and a pressure accumulation provided in the diesel engine 40. 1 shows a schematic configuration of a fuel injection device 50.
　ディーゼルエンジン４０は、ピストン４２がクランクシャフト４３の回転に伴って気筒４１内を往復動し、圧縮行程で気筒４１内にディーゼル燃料が噴射されることで気筒４１内で爆発を生じピストン４２が押し下げられてクランクシャフト４３がさらに回転させられることで駆動する。
　このディーゼルエンジン４０には、クランクシャフト４３を強制的に回転させるためのクランク角調節手段としてのスタータ４４と、クランクシャフト４３の回転位相であるクランク角を検出するためのクランク角センサ４５が設けられている。 In the diesel engine 40, the piston 42 reciprocates in the cylinder 41 as the crankshaft 43 rotates, and diesel fuel is injected into the cylinder 41 during the compression stroke, causing an explosion in the cylinder 41 and pushing down the piston 42. Then, the crankshaft 43 is driven by being further rotated.
The diesel engine 40 is provided with a starter 44 as a crank angle adjusting means for forcibly rotating the crankshaft 43 and a crank angle sensor 45 for detecting a crank angle that is a rotation phase of the crankshaft 43. ing.
　また、ディーゼルエンジン４０の気筒４１内に燃料を噴射するための蓄圧式燃料噴射装置５０は、燃料タンク１と、電動低圧ポンプ２と、高圧ポンプ５と、コモンレール１０と、燃料噴射弁１３等を主たる要素として備えている。 Further, a pressure accumulation type fuel injection device 50 for injecting fuel into the cylinder 41 of the diesel engine 40 includes a fuel tank 1, an electric low-pressure pump 2, a high-pressure pump 5, a common rail 10, a fuel injection valve 13, and the like. It is provided as the main element.
　電動低圧ポンプ２と高圧ポンプ５の加圧室５ａは低圧燃料通路１８で接続され、高圧ポンプ５とコモンレール１０、及びコモンレール１０と燃料噴射弁１３は高圧燃料通路３７、３９で接続されている。また、高圧ポンプ５やコモンレール１０、燃料噴射弁１３等には、排出される燃料を燃料タンク１に戻すための燃料リーク通路３０ａ～３０ｃが接続されている。 The pressurizing chamber 5a of the electric low pressure pump 2 and the high pressure pump 5 is connected by a low pressure fuel passage 18, and the high pressure pump 5 and the common rail 10, and the common rail 10 and the fuel injection valve 13 are connected by high pressure fuel passages 37 and 39. In addition, fuel leak passages 30a to 30c for returning discharged fuel to the fuel tank 1 are connected to the high pressure pump 5, the common rail 10, the fuel injection valve 13, and the like.
　電動低圧ポンプ２は、燃料タンク１内の低圧燃料を、低圧燃料通路１８を介して高圧ポンプ５の加圧室５ａに対して圧送する。図１に示される電動低圧ポンプ２は、低圧燃料が貯蔵された燃料タンク１内に備えられたインタンクの電動低圧ポンプであって、バッテリーから供給される電圧によって駆動され、供給電圧に応じた出力で所定の流量の低圧燃料を圧送する。 The electric low-pressure pump 2 pumps the low-pressure fuel in the fuel tank 1 to the pressurizing chamber 5 a of the high-pressure pump 5 through the low-pressure fuel passage 18. An electric low-pressure pump 2 shown in FIG. 1 is an in-tank electric low-pressure pump provided in a fuel tank 1 in which low-pressure fuel is stored. The electric low-pressure pump 2 is driven by a voltage supplied from a battery and corresponds to the supply voltage. A low pressure fuel with a predetermined flow rate is pumped at the output.
　高圧ポンプ５は、電動低圧ポンプ２によって圧送され、燃料吸入弁６を介して加圧室５ａに導入された低圧燃料をプランジャ７によって加圧し、燃料吐出弁９及び高圧燃料通路３７を介して、高圧燃料をコモンレール１０に圧送する。図１に示す蓄圧式燃料噴射装置５０の例では、高圧ポンプ５内に送られる低圧燃料は、一旦、カム１５が収容されたカム室１６内に流れ込み、そこからさらに加圧室５ａに送られる。 The high-pressure pump 5 is pumped by the electric low-pressure pump 2 and pressurized by the plunger 7 with the low-pressure fuel introduced into the pressurizing chamber 5 a via the fuel intake valve 6, and via the fuel discharge valve 9 and the high-pressure fuel passage 37. High pressure fuel is pumped to the common rail 10. In the example of the accumulator fuel injection device 50 shown in FIG. 1, the low-pressure fuel sent into the high-pressure pump 5 once flows into the cam chamber 16 in which the cam 15 is accommodated, and is further sent from there to the pressurizing chamber 5a. .
　また、カム室１６と加圧室５ａとを接続する低圧燃料通路１８の途中には流量制御弁８が備えられ、要求されるレール圧及び要求噴射量に応じて、加圧室５ａに供給される低圧燃料の流量が調節される。加圧室５ａに供給される低圧燃料の流量が調節されることで、高圧ポンプ５からの高圧燃料の吐出量が調節される。 A flow control valve 8 is provided in the middle of the low pressure fuel passage 18 connecting the cam chamber 16 and the pressurizing chamber 5a, and is supplied to the pressurizing chamber 5a according to the required rail pressure and the required injection amount. The flow of low pressure fuel is adjusted. The discharge amount of the high-pressure fuel from the high-pressure pump 5 is adjusted by adjusting the flow rate of the low-pressure fuel supplied to the pressurizing chamber 5a.
　また、流量制御弁８よりも上流側には、低圧燃料流路１８から分岐する通路に接続され、流量制御弁８と並列的に配置された圧力調整弁１４が備えられており、圧力調整弁１４はさらに燃料タンク１に通じる燃料リーク通路３０ａに接続されている。この圧力調整弁１４は、前後の差圧、すなわち、低圧燃料通路１８内の圧力と、燃料リーク通路３０ａ内の圧力との差が所定値を越えたときに開弁されるオーバーフローバルブが用いられている。 Further, on the upstream side of the flow control valve 8, there is provided a pressure adjustment valve 14 connected to a passage branched from the low-pressure fuel flow path 18 and arranged in parallel with the flow control valve 8. Further, 14 is connected to a fuel leak passage 30 a communicating with the fuel tank 1. The pressure regulating valve 14 is an overflow valve that is opened when the difference between the front and rear pressures, that is, the pressure in the low pressure fuel passage 18 and the pressure in the fuel leak passage 30a exceeds a predetermined value. ing.
　高圧ポンプ５を駆動するカム１５は、ディーゼルエンジン４０のクランクシャフト４３にギアを介して連結されたカムシャフトに固定されており、カム１５の回転数はディーゼルエンジン４０の回転数に比例する。また、図１に示す蓄圧式燃料噴射装置５０の高圧ポンプ５は、二本のプランジャ７が、山数が二つのカム１５によって押し上げられ、二つの加圧室５ａ内で低圧燃料が加圧されて、各加圧室５ａからコモンレール１０に対して高圧燃料が圧送される。したがって、カム１５一回転当たりの高圧ポンプ５の圧送回数が４回となる。 The cam 15 that drives the high-pressure pump 5 is fixed to a camshaft connected to the crankshaft 43 of the diesel engine 40 via a gear, and the rotational speed of the cam 15 is proportional to the rotational speed of the diesel engine 40. Further, in the high pressure pump 5 of the accumulator fuel injection device 50 shown in FIG. 1, the two plungers 7 are pushed up by the cams 15 having two peaks, and the low pressure fuel is pressurized in the two pressurizing chambers 5a. Thus, high-pressure fuel is pumped from each pressurizing chamber 5 a to the common rail 10. Therefore, the number of pumping times of the high-pressure pump 5 per rotation of the cam 15 is four.
　コモンレール１０は、高圧ポンプ５から圧送される高圧燃料を蓄積し、高圧燃料通路３９を介して接続された複数の燃料噴射弁１３に対して高圧燃料を供給する。このコモンレール１０にはレール圧センサ２１及び圧力制御弁１２が取り付けられている。圧力制御弁１２は、例えば電磁比例制御弁が用いられ、コモンレール１０から燃料リーク通路３０ｂに排出する燃料のリーク量が調節され、当該リーク量に応じてレール圧が調整される。 The common rail 10 accumulates the high-pressure fuel pumped from the high-pressure pump 5 and supplies the high-pressure fuel to the plurality of fuel injection valves 13 connected via the high-pressure fuel passage 39. A rail pressure sensor 21 and a pressure control valve 12 are attached to the common rail 10. For example, an electromagnetic proportional control valve is used as the pressure control valve 12, the amount of fuel leaked from the common rail 10 to the fuel leak passage 30 b is adjusted, and the rail pressure is adjusted according to the amount of leak.
　また、コモンレール１０に備えられたレール圧センサ２１で検出されるレール圧の信号は制御装置７０に送られる。制御装置７０は、検出されるレール圧が目標レール圧となるように、コモンレール１０に備えられた圧力制御弁１２又は高圧ポンプ５に備えられた流量制御弁８の制御を行う。 Further, a rail pressure signal detected by the rail pressure sensor 21 provided in the common rail 10 is sent to the control device 70. The control device 70 controls the pressure control valve 12 provided in the common rail 10 or the flow rate control valve 8 provided in the high-pressure pump 5 so that the detected rail pressure becomes the target rail pressure.
　コモンレール１０に接続された燃料噴射弁１３は、噴射孔が設けられたノズルボディと噴射孔を閉塞するノズルニードルとを備え、ノズルニードルの後端側に作用する背圧が逃されることによって噴射孔が開かれることで、コモンレール１０から供給される高圧燃料をディーゼルエンジン４０の気筒４１内に噴射する。燃料噴射弁１３は、例えば、背圧制御部として電磁ソレノイドが備えられた電磁制御型のマグネットインジェクタや、背圧制御部としてピエゾ素子が備えられた電歪型のピエゾインジェクタが用いられる。これら例示される燃料噴射弁１３は、レール圧が噴射可能圧力以上になっており、高圧燃料が供給された状態において正常な噴射が可能になる。本実施形態では、燃料噴射弁１３として、背圧を逃すための通路以外にリーク通路が設けられた構造の燃料噴射弁が用いられている。 The fuel injection valve 13 connected to the common rail 10 includes a nozzle body provided with an injection hole and a nozzle needle that closes the injection hole, and the back pressure acting on the rear end side of the nozzle needle is released to release the injection hole. Is opened, the high-pressure fuel supplied from the common rail 10 is injected into the cylinder 41 of the diesel engine 40. The fuel injection valve 13 is, for example, an electromagnetic control type magnet injector provided with an electromagnetic solenoid as a back pressure control unit, or an electrostrictive type piezo injector provided with a piezo element as a back pressure control unit. In these exemplified fuel injection valves 13, the rail pressure is equal to or higher than the injectable pressure, and normal injection is possible in a state where high-pressure fuel is supplied. In this embodiment, as the fuel injection valve 13, a fuel injection valve having a structure in which a leak passage is provided in addition to a passage for releasing back pressure is used.
２．ディーゼルエンジンの制御装置
　本実施形態のディーゼルエンジン４０の制御装置７０は、高圧ポンプ５に備えられた流量制御弁８による高圧ポンプ５の吐出量制御や、コモンレール１０に備えられた圧力制御弁１２による高圧排出制御、燃料噴射弁１３によるディーゼルエンジン４０の気筒４１内への燃料噴射制御、ディーゼルエンジン４０のアイドリングストップ制御、ディーゼルエンジン４０のクランク角調節制御を行う。 2. Control Device 70 of Diesel Engine The control device 70 of the diesel engine 40 of the present embodiment is based on the discharge amount control of the high pressure pump 5 by the flow rate control valve 8 provided on the high pressure pump 5 and the pressure control valve 12 provided on the common rail 10. High pressure discharge control, fuel injection control into the cylinder 41 of the diesel engine 40 by the fuel injection valve 13, idling stop control of the diesel engine 40, and crank angle adjustment control of the diesel engine 40 are performed.
　図２は、本実施形態のディーゼルエンジン４０の制御装置７０の構成のうち、主としてアイドリングストップ制御及びクランク角調節制御に関する部分を機能的なブロックで表した図を示している。この制御装置７０は、公知の構成からなるマイクロコンピュータを中心に構成されており、アイドリングストップ制御部７１と、クランク角検出部７３と、レール圧検出部７５と、燃料噴射弁制御部７６と、クランク角制御部７７とを備えている。これらの各部は、具体的にはマイクロコンピュータによるプログラムの実行によって実現される。 FIG. 2 is a functional block diagram showing a part related to idling stop control and crank angle adjustment control in the configuration of the control device 70 of the diesel engine 40 of the present embodiment. The control device 70 is configured around a microcomputer having a known configuration, and includes an idling stop control unit 71, a crank angle detection unit 73, a rail pressure detection unit 75, a fuel injection valve control unit 76, And a crank angle control unit 77. Specifically, each of these units is realized by executing a program by a microcomputer.
　この制御装置７０には、コモンレール１０に備えられたレール圧センサ２１やディーゼルエンジン４０に備えられたクランク角センサ４５、車両に備えられた車速Vを検出する車速センサ、アクセルペダルの操作量Accを検出するためのアクセルセンサ、ブレーキペダルの操作量Brkを検出するためのブレーキセンサ、変速機のクラッチ位置Cpを検出するクラッチセンサ、変速機のシフト位置Gpを検出するためのシフトポジションセンサ等の各種スイッチやセンサ類が接続されている。 The control device 70 includes a rail pressure sensor 21 provided in the common rail 10, a crank angle sensor 45 provided in the diesel engine 40, a vehicle speed sensor that detects a vehicle speed V provided in the vehicle, and an accelerator pedal operation amount Acc. Accelerator sensor for detecting, brake sensor for detecting brake pedal operation amount Brk, clutch sensor for detecting clutch position Cp of transmission, shift position sensor for detecting shift position Gp of transmission, etc. Switches and sensors are connected.
　このうち、燃料噴射弁制御部７６は、燃料噴射弁１３の駆動制御を行う。本実施形態の燃料噴射弁１３は電磁ソレノイドが備えられたマグネットインジェクタであり、燃料噴射弁制御部７６はディーゼルエンジン４０の運転状態に応じて算出される燃料噴射量Qに応じて電磁ソレノイドに対する通電の制御信号S1を出力することで、燃料噴射弁１３の噴射孔の開閉を制御する。 Among these, the fuel injection valve control unit 76 performs drive control of the fuel injection valve 13. The fuel injection valve 13 of this embodiment is a magnet injector provided with an electromagnetic solenoid, and the fuel injection valve control unit 76 energizes the electromagnetic solenoid according to the fuel injection amount Q calculated according to the operating state of the diesel engine 40. The control signal S1 is output to control the opening and closing of the injection hole of the fuel injection valve 13.
　クランク角検出部７３は、クランク角センサの信号Scを読み取り、クランク角Caを検出する。検出されたクランク角Caは、クランク角制御部７７に送られる。レール圧検出部７５は、レール圧センサ２１の信号Spを読み取り、レール圧Prを検出する。検出されたレール圧Prは、アイドリングストップ制御部７１及びクランク角制御部７７に送られる。 The crank angle detector 73 reads the crank angle sensor signal Sc and detects the crank angle Ca. The detected crank angle Ca is sent to the crank angle control unit 77. The rail pressure detector 75 reads the signal Sp of the rail pressure sensor 21 and detects the rail pressure Pr. The detected rail pressure Pr is sent to the idling stop control unit 71 and the crank angle control unit 77.
　アイドリングストップ制御部７１は、エンジン停止判定部７１ａ及びエンジン再始動判定部７１ｂを有している。アイドリングストップ制御は、車両が信号待ちをしている間や、人の乗り降り、物の積み下ろしをしている間等、車両が短時間停止するような状況において、その間の燃料の消費を抑えたり排気ガスの排出を抑えたりするために、ディーゼルエンジン４０のスイッチをオンにしたままディーゼルエンジン４０を一旦停止させる制御である。 The idling stop control unit 71 includes an engine stop determination unit 71a and an engine restart determination unit 71b. Idling stop control suppresses fuel consumption or exhausts during situations where the vehicle stops for a short time, such as when the vehicle is waiting for a signal, while a person is getting on or off, or when loading or unloading an object. In order to suppress gas emission, the diesel engine 40 is temporarily stopped while the switch of the diesel engine 40 is kept on.
　エンジン停止判定部７１ａ及びエンジン再始動判定部７１ｂの構成は特に制限されるものではないが、本実施形態の制御装置７０の例では、エンジン停止判定部７１ａは、ディーゼルエンジン４０の回転数Neやアクセルペダルの操作量Acc、ブレーキペダルの操作量Brk、変速機のクラッチ位置Cp、変速機のシフト位置Gp等の情報を読込み、これらの情報に基づきあらかじめ設定されたアイドリングストップ条件が成立したか否かを判別する。 The configurations of the engine stop determination unit 71a and the engine restart determination unit 71b are not particularly limited, but in the example of the control device 70 of the present embodiment, the engine stop determination unit 71a is configured such that the rotational speed Ne of the diesel engine 40 is Read information such as accelerator pedal operation amount Acc, brake pedal operation amount Brk, transmission clutch position Cp, transmission shift position Gp, etc., and whether or not the idling stop condition set in advance based on these information is satisfied Is determined.
　そして、アイドリングストップ条件が成立したときには、燃料噴射弁制御部７６に対して燃料噴射を中断するよう指示信号S2を送るとともに、アイドリングストップ条件が成立したことを示す信号Sesをエンジン再始動判定部７１ｂ及びクランク角制御部７７に送る。 When the idling stop condition is satisfied, an instruction signal S2 is sent to the fuel injection valve control unit 76 to interrupt the fuel injection, and a signal Ses indicating that the idling stop condition is satisfied is sent to the engine restart determining unit 71b. And sent to the crank angle control unit 77.
　また、本実施形態の制御装置７０のエンジン再始動判定部７１ｂは、エンジン停止判定部７１ａからアイドリングストップ条件が成立したことを示す信号Sesを受け取ると、アクセルペダルの操作量Acc、ブレーキペダルの操作量Brk、変速機のクラッチ位置Cp、変速機のシフト位置Gp等の情報を読込み、これらの情報に基づきあらかじめ設定された再始動条件が成立したか否かを判別する。 In addition, when the engine restart determination unit 71b of the control device 70 of the present embodiment receives the signal Ses indicating that the idling stop condition is satisfied from the engine stop determination unit 71a, the accelerator pedal operation amount Acc, the brake pedal operation Information such as the amount Brk, the clutch position Cp of the transmission, the shift position Gp of the transmission, etc. is read, and based on these information, it is determined whether a preset restart condition is satisfied.
　そして、再始動条件が成立したときには、クランク角制御部７７に再始動条件が成立したことを示す信号Srsを送るとともに、燃料噴射弁制御部７６に燃料噴射を許可する信号S3を送る。 When the restart condition is satisfied, a signal Srs indicating that the restart condition is satisfied is sent to the crank angle control unit 77, and a signal S3 permitting fuel injection is sent to the fuel injection valve control unit 76.
　クランク角制御部７７は、クランクシャフト４３の回転位相をずらすためのクランク角調節手段としてのスタータ４４に作動信号S4を出力する。本実施形態の制御装置７０のクランク角制御部７７は、ディーゼルエンジン４０がアイドリングストップ制御による停止した後の再始動条件成立時にレール圧Prが噴射可能圧力Pr0未満の場合に、レール圧Prが噴射可能圧力Pr0以上に速やかに到達するように、スタータ４４に対してディーゼルエンジン４０のクランク角Caをずらすための作動信号S4を出力する。 The crank angle control unit 77 outputs an operation signal S4 to the starter 44 as crank angle adjusting means for shifting the rotation phase of the crankshaft 43. The crank angle control unit 77 of the control device 70 of the present embodiment injects the rail pressure Pr when the rail pressure Pr is less than the injectable pressure Pr0 when the restart condition is satisfied after the diesel engine 40 is stopped by the idling stop control. An operation signal S4 for shifting the crank angle Ca of the diesel engine 40 is output to the starter 44 so as to quickly reach the possible pressure Pr0 or higher.
　また、本実施形態の制御装置７０のクランク角制御部７７は、ディーゼルエンジン４０がアイドリングストップ制御によって停止した後の再始動条件成立時にレール圧Prが噴射可能圧力Pr0以上である場合には、ディーゼルエンジン４０において燃料噴射前に必要な分の圧縮行程が行われる位置からクランキングが開始されるように、スタータ４４に対してディーゼルエンジン４０のクランク角Caをずらすための作動信号Sstを出力する。 In addition, the crank angle control unit 77 of the control device 70 of the present embodiment is configured so that the diesel engine 40 is diesel-powered when the rail pressure Pr is equal to or higher than the injectable pressure Pr0 when the restart condition is satisfied after the diesel engine 40 is stopped by the idling stop control. An operation signal Sst for shifting the crank angle Ca of the diesel engine 40 is output to the starter 44 so that cranking is started from a position where a necessary compression stroke is performed before fuel injection in the engine 40.
　すでに述べたとおり、ディーゼルエンジン４０の始動は、ディーゼルエンジン４０が圧縮行程にあり、レール圧Prが噴射可能圧力Pr0以上になっていることが条件となる。しかしながら、ディーゼルエンジン４０の場合、ディーゼルエンジン４０が圧縮行程になるよりも、レール圧Prが噴射可能圧力Pr0以上になる方が、多くのクランクシャフト４３の回転変位が必要であるため、ディーゼルエンジン４０の停止中にレール圧Prが噴射可能圧力Pr0未満になった時には、レール圧Prの速やかな上昇が優先される。 As described above, the diesel engine 40 is started on the condition that the diesel engine 40 is in the compression stroke and the rail pressure Pr is equal to or higher than the injectable pressure Pr0. However, in the case of the diesel engine 40, more rotational displacement of the crankshaft 43 is required when the rail pressure Pr becomes equal to or higher than the injectable pressure Pr0 than when the diesel engine 40 is in the compression stroke. When the rail pressure Pr becomes less than the injectable pressure Pr0 during the stop, the rapid increase of the rail pressure Pr is prioritized.
３．クランク角調節の具体的方法
　次に、制御装置７０によって行われる、アイドリングストップ制御によるディーゼルエンジン４０の停止中に行われるクランク角の調節方法について具体的に説明する。 3. Specific Method of Crank Angle Adjustment Next, the crank angle adjustment method performed by the control device 70 while the diesel engine 40 is stopped by idling stop control will be specifically described.
　上述したとおり、本実施形態の制御装置７０は、アイドリングストップ制御によるディーゼルエンジン４０の停止中にレール圧Prが噴射可能圧力Pr0未満になった時には、再始動時にレール圧Prが速やかに噴射可能圧力Pr0以上に到達するようにクランク角Caがずらされる（制御モード１）。また、本実施形態の制御装置７０は、ディーゼルエンジン４０の停止中でもレール圧Prが噴射可能圧力Pr0以上に維持されている場合には、再始動時に燃料噴射前に必要な分の圧縮行程が行われる位置からクランキングが開始されるようにクランク角Caがずらされる（制御モード２）。 As described above, when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine 40 is stopped by the idling stop control, the control device 70 of the present embodiment promptly causes the rail pressure Pr to be injectable during restart. The crank angle Ca is shifted so as to reach Pr0 or more (control mode 1). In addition, the control device 70 of the present embodiment performs the compression stroke necessary for fuel injection before restarting when the rail pressure Pr is maintained at the injectable pressure Pr0 or higher even when the diesel engine 40 is stopped. The crank angle Ca is shifted so that cranking is started from the position where it is positioned (control mode 2).
（１）レール圧が噴射可能圧力未満になったときの制御（制御モード１）
　図３～図６は、ディーゼルエンジン４０の停止中にレール圧Prが噴射可能圧力Pr0未満になったときに実行されるクランク角の調節方法を説明するための図である。それぞれの図中、横軸がディーゼルエンジン４０のクランク角Caを示し、縦軸が高圧ポンプ５のプランジャ７のリフト量Lplを示している。それぞれレール圧Prを大気圧から噴射可能圧力Pr0以上にするまでに高圧ポンプ５からの圧送回数が最大１．５圧送必要な蓄圧式燃料噴射装置５０の例である。また、各図はディーゼルエンジン４０の気筒数が四つの場合を例に採ったものであり、各燃料噴射タイミングに燃料の噴射が行われる気筒が♯１～♯４で示されている。各図において、プランジャのリフト位置が増大している行程が燃料圧送行程を表し、プランジャのリフト量が減少している行程が燃料吸入行程を表している。 (1) Control when the rail pressure becomes less than the injectable pressure (control mode 1)
FIGS. 3 to 6 are diagrams for explaining a crank angle adjustment method executed when the rail pressure Pr becomes lower than the injectable pressure Pr0 while the diesel engine 40 is stopped. In each figure, the horizontal axis represents the crank angle Ca of the diesel engine 40, and the vertical axis represents the lift amount Lpl of the plunger 7 of the high-pressure pump 5. This is an example of the accumulator type fuel injection device 50 in which the maximum number of times of pumping from the high-pressure pump 5 is required until the rail pressure Pr is changed from atmospheric pressure to the injectable pressure Pr0 or more. Each figure shows an example in which the number of cylinders of the diesel engine 40 is four, and cylinders in which fuel is injected at each fuel injection timing are indicated by # 1 to # 4. In each figure, the stroke in which the lift position of the plunger is increased represents the fuel pressure feed stroke, and the stroke in which the lift amount of the plunger is decreased represents the fuel intake stroke.
　このうち、図３は、ディーゼルエンジン４０のクランクシャフト４３が一回転（３６０°回転）する間に高圧ポンプ５のプランジャ７が二回往復動し、プランジャ７の上死点付近で燃料噴射が行われるように燃料噴射タイミングとプランジャ７の往復動とが同期している蓄圧式燃料噴射装置の例を示している。また、図４は、ディーゼルエンジン４０のクランクシャフト４３が一回転（３６０°回転）する間に、高圧ポンプ５のプランジャ７が二回往復動し、プランジャ７の下死点付近で燃料噴射が行われるように燃料噴射タイミングとプランジャ７の往復動とが同期している蓄圧式燃料噴射装置の例を示している。さらに、図５及び図６は、ディーゼルエンジン４０のクランクシャフト４３が一回転（３６０°回転）する間に、高圧ポンプ５のプランジャ７が一回半往復動し、毎回、燃料噴射タイミングでのプランジャ７のリフト位置が異なる蓄圧式燃料噴射装置の例を示している。 Among these, FIG. 3 shows that the plunger 7 of the high-pressure pump 5 reciprocates twice while the crankshaft 43 of the diesel engine 40 rotates once (360 ° rotation), and fuel injection is performed near the top dead center of the plunger 7. As shown, an example of a pressure accumulation type fuel injection device in which the fuel injection timing and the reciprocation of the plunger 7 are synchronized is shown. 4 shows that the plunger 7 of the high-pressure pump 5 reciprocates twice while the crankshaft 43 of the diesel engine 40 makes one rotation (360 ° rotation), and fuel injection is performed near the bottom dead center of the plunger 7. As shown, an example of a pressure accumulation type fuel injection device in which the fuel injection timing and the reciprocation of the plunger 7 are synchronized is shown. 5 and 6 show that the plunger 7 of the high-pressure pump 5 reciprocates once and a half while the crankshaft 43 of the diesel engine 40 makes one rotation (360 ° rotation), and the plunger at the fuel injection timing every time. 7 shows an example of a pressure accumulating fuel injection device having different lift positions.
　上述したように、本実施形態の制御装置７０は、アイドリングストップ制御によるディーゼルエンジン４０の停止中に、ディーゼルエンジン４０の再始動時にレール圧Prが速やかに噴射可能圧力Pr0以上に到達するようにクランク角Caをずらす制御を行う。ただし、クランク角Caをずらす際の目標位置Catgtは、燃料噴射が行われる際のプランジャ７のリフト位置によって異なってくる。 As described above, the control device 70 of the present embodiment performs cranking so that the rail pressure Pr quickly reaches the injectable pressure Pr0 or more when the diesel engine 40 is restarted while the diesel engine 40 is stopped by the idling stop control. Control to shift the corner Ca. However, the target position Catgt when shifting the crank angle Ca differs depending on the lift position of the plunger 7 when fuel injection is performed.
　図３の例において、プランジャ７が上死点にあるクランク角Caで燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、その燃料噴射タイミングまでに２２５°以上のクランク角Caの変位が必要となる。高圧ポンプ５の加圧室５ａに燃料を供給する低圧ポンプが本実施形態の蓄圧式燃料噴射装置５０の電動低圧ポンプ２のようにディーゼルエンジン４０の回転数に依存しないで駆動するポンプの場合には、ディーゼルエンジン４０の始動前であっても加圧室５ａに燃料を充填することが可能である。そのため、このような低圧ポンプを備えている場合には、クランク角Caをずらす目標位置Catgtが高圧ポンプ５の燃料圧送行程中となっていても構わない。 In the example of FIG. 3, if the plunger 7 wants to start fuel injection at the crank angle Ca at the top dead center, in order to ensure that the number of pumps of the high-pressure pump 5 is 1.5, the fuel injection A crank angle Ca displacement of 225 ° or more is required by the timing. When the low-pressure pump that supplies fuel to the pressurizing chamber 5a of the high-pressure pump 5 is a pump that is driven without depending on the rotational speed of the diesel engine 40, such as the electric low-pressure pump 2 of the accumulator fuel injection device 50 of the present embodiment. Can fill the pressurizing chamber 5a with fuel even before the diesel engine 40 is started. Therefore, when such a low-pressure pump is provided, the target position Catgt for shifting the crank angle Ca may be in the fuel pressure feed stroke of the high-pressure pump 5.
　例えば、アイドリングストップ制御によってクランク角Caが４５０°のＡの位置でディーゼルエンジン４０が停止したとする。このとき、次に燃料噴射タイミングが到来する気筒♯２から燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、クランク角Caの目標位置Catgtを３１５°に設定して、クランク角Caを－１３５°ずらす必要がある。また、その次に燃料噴射タイミングが到来する気筒♯１から燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、クランク角Caの目標位置Catgtを４９５°に設定して、クランク角Caを＋４５°ずらす必要がある。さらに、気筒♯３から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを６７５°に設定してクランク角Caを＋２２５°ずらす必要があり、気筒♯４から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを８５５°に設定してクランク角Caを＋４０５°ずらす必要がある。 For example, it is assumed that the diesel engine 40 is stopped at a position where the crank angle Ca is 450 ° by idling stop control. At this time, if it is desired to start fuel injection from the cylinder # 2 at which the fuel injection timing comes next, the target position of the crank angle Ca is set in order to ensure that the number of pumps of the high-pressure pump 5 is 1.5. It is necessary to set Catgt to 315 ° and shift the crank angle Ca by -135 °. Further, if it is desired to start fuel injection from the cylinder # 1 at which the fuel injection timing comes next, in order to ensure that the number of pumping times of the high pressure pump 5 is 1.5 pumping, the target position of the crank angle Ca is set. It is necessary to set Catgt to 495 ° and shift the crank angle Ca by + 45 °. Further, if it is desired to start fuel injection from cylinder # 3, it is necessary to set the target position Catgt of crank angle Ca to 675 ° and shift crank angle Ca by + 225 °. If fuel injection is to be started from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 855 ° and shift the crank angle Ca by + 405 °.
　このうち、クランク角Caをずらす量が最小となるのは気筒♯１から燃料噴射を開始する場合であるため、クランク角Caの目標位置Catgt(A)が４９５°に設定されて、ディーゼルエンジン４０の再始動時までにクランク角Caがずらされる。その結果、クランク角Caをずらす時間が最短になってクランク角Caをずらす負荷が低減されるとともに、ディーゼルエンジン４０の再始動時にクランキングを開始させてから最小時間での高圧燃料の正常噴射が可能になる。 Of these, the amount by which the crank angle Ca is shifted is minimized when fuel injection is started from the cylinder # 1, so the target position Catgt (A) of the crank angle Ca is set to 495 °, and the diesel engine 40 The crank angle Ca is shifted by the time of restart. As a result, the time for shifting the crank angle Ca is minimized, the load for shifting the crank angle Ca is reduced, and normal injection of high-pressure fuel in the minimum time after cranking is started when the diesel engine 40 is restarted. It becomes possible.
　また、アイドリングストップ制御によってクランク角Caが３６０°のＢの位置でディーゼルエンジン４０が停止したとする。このとき、次に燃料噴射タイミングが到来する気筒♯２から燃料噴射を開始したいとすると、クランク角Caの目標位置Catgtを３１５°に設定して、クランク角Caを－４５°ずらす必要がある。また、その次に燃料噴射タイミングが到来する気筒♯１から燃料噴射を開始したいとすると、クランク角Caの目標位置Catgtを４９５°に設定して、クランク角Caを＋１３５°ずらす必要がある。さらに、気筒♯３から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを６７５°に設定してクランク角Caを＋３１５°ずらす必要があり、気筒♯４から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを８５５°に設定してクランク角Caを＋４９５°ずらす必要がある。 Suppose that the diesel engine 40 is stopped at a position B where the crank angle Ca is 360 ° by the idling stop control. At this time, if it is desired to start fuel injection from the cylinder # 2 where the fuel injection timing comes next, it is necessary to set the target position Catgt of the crank angle Ca to 315 ° and shift the crank angle Ca by −45 °. If it is desired to start fuel injection from the cylinder # 1 at which the fuel injection timing comes next, it is necessary to set the target position Catgt of the crank angle Ca to 495 ° and shift the crank angle Ca by + 135 °. Further, if it is desired to start fuel injection from cylinder # 3, it is necessary to set the target position Catgt of crank angle Ca to 675 ° and shift crank angle Ca by + 315 °, and if it is desired to start fuel injection from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 855 ° and shift the crank angle Ca by + 495 °.
　このうち、クランク角Caをずらす量が最小となるのは気筒♯２から燃料噴射を開始する場合であるため、クランク角Caの目標位置Catgt(B)が３１５°に設定されて、ディーゼルエンジン４０の再始動時までにクランク角Caがずらされる。その結果、クランク角Caをずらす時間が最短になってクランク角Caをずらす負荷が低減されるとともに、ディーゼルエンジン４０の再始動時にクランキングを開始させてから最小時間での高圧燃料の正常噴射が可能になる。 Of these, the amount of shift of the crank angle Ca is minimized when fuel injection is started from the cylinder # 2, so the target position Catgt (B) of the crank angle Ca is set to 315 °, and the diesel engine 40 The crank angle Ca is shifted by the time of restart. As a result, the time for shifting the crank angle Ca is minimized, the load for shifting the crank angle Ca is reduced, and normal injection of high-pressure fuel in the minimum time after cranking is started when the diesel engine 40 is restarted. It becomes possible.
　さらに、アイドリングストップ制御によってクランク角Caが４０５°のＣの位置でディーゼルエンジン４０が停止したとする。このとき、次に燃料噴射タイミングが到来する気筒♯２から燃料噴射を開始したいとすると、クランク角Caの目標位置Catgtを３１５°に設定して、クランク角Caを－９０°ずらす必要がある。また、その次に燃料噴射タイミングが到来する気筒♯１から燃料噴射を開始したいとすると、クランク角Caの目標位置Catgtを４９５°に設定して、クランク角Caを＋９０°ずらす必要がある。さらに、気筒♯３から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを６７５°に設定してクランク角Caを＋２７０°ずらす必要があり、気筒♯４から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを８５５°に設定してクランク角Caを＋４５０°ずらす必要がある。 Furthermore, it is assumed that the diesel engine 40 is stopped at a position where the crank angle Ca is 405 ° by the idling stop control. At this time, if it is desired to start fuel injection from the cylinder # 2 at which the fuel injection timing comes next, it is necessary to set the target position Catgt of the crank angle Ca to 315 ° and shift the crank angle Ca by −90 °. If it is desired to start fuel injection from the cylinder # 1 at which the fuel injection timing comes next, it is necessary to set the target position Catgt of the crank angle Ca to 495 ° and shift the crank angle Ca by + 90 °. Further, if it is desired to start fuel injection from cylinder # 3, it is necessary to set the target position Catgt of crank angle Ca to 675 ° and shift crank angle Ca by + 270 °, and if it is desired to start fuel injection from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 855 ° and shift the crank angle Ca by + 450 °.
　このうち、クランク角Caをずらす量が最小となるのは気筒♯２又は気筒♯１から燃料噴射を開始する場合であるため、クランク角Caの目標位置Catgt(C)が３１５°又は４９５°に設定されて、ディーゼルエンジン４０の再始動時までにクランク角Caがずらされる。その結果、クランク角Caをずらす時間が最短になってクランク角Caをずらす負荷が低減されるとともに、ディーゼルエンジン４０の再始動時にクランキングを開始させてから最小時間での高圧燃料の正常噴射が可能になる。 Among these, the amount by which the crank angle Ca is shifted is minimized when the fuel injection is started from the cylinder # 2 or the cylinder # 1, so the target position Catgt (C) of the crank angle Ca is set to 315 ° or 495 °. The crank angle Ca is shifted until the diesel engine 40 is restarted. As a result, the time for shifting the crank angle Ca is minimized, the load for shifting the crank angle Ca is reduced, and normal injection of high-pressure fuel in the minimum time after cranking is started when the diesel engine 40 is restarted. It becomes possible.
　さらにまた、アイドリングストップ制御によってクランク角Caが４９５°のＤの位置でディーゼルエンジン４０が停止したとする。このとき、次の次に燃料噴射タイミングが到来する気筒♯１から燃料噴射を開始したいとすると、クランク角Caの目標位置Catgtは４９５°であるため、クランク角Caをずらす必要がない。そのため、ディーゼルエンジン４０の再始動時にこの状態（目標位置Catgt(D)）からクランキングを開始させることで、最小時間での高圧燃料の正常噴射が可能になる。 Furthermore, it is assumed that the diesel engine 40 is stopped at the position D where the crank angle Ca is 495 ° by the idling stop control. At this time, if it is desired to start fuel injection from the cylinder # 1 at which the next fuel injection timing comes, the target position Catgt of the crank angle Ca is 495 °, so there is no need to shift the crank angle Ca. For this reason, when the diesel engine 40 is restarted, cranking is started from this state (target position Catgt (D)), whereby normal injection of high-pressure fuel in a minimum time becomes possible.
　この他、図４の例のように、気筒♯１～♯４のうちの気筒♯２においてプランジャ７が下死点にあるクランク角Ca（５４０°）で燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、その燃料噴射タイミングまでに３１５°以上のクランク角Caの変位が必要となる。 In addition to this, as in the example of FIG. 4, if it is desired to start fuel injection at a crank angle Ca (540 °) at which the plunger 7 is at the bottom dead center in the cylinder # 2 of the cylinders # 1 to # 4, the high pressure pump In order to ensure that the number of times of pumping 5 is 1.5 pumping, displacement of the crank angle Ca of 315 ° or more is required before the fuel injection timing.
　また、燃料噴射タイミングごとにプランジャ７のリフト位置が異なる図５及び図６の例において、図５（ａ）の例のように、プランジャ７が下降途中にある位置（クランク角５４０°）で燃料噴射が行われる気筒♯２で燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、その燃料噴射タイミングまでに３６０°以上のクランク角Caの変位が必要となる。また、図５（ｂ）の例のように、プランジャ７が上死点にある位置（クランク角７２０°）で燃料噴射が行われる気筒♯１で燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、その燃料噴射タイミングまでに３００°以上のクランク角Caの変位が必要となる。 Further, in the example of FIGS. 5 and 6 in which the lift position of the plunger 7 is different at each fuel injection timing, the fuel is produced at the position where the plunger 7 is being lowered (crank angle 540 °) as in the example of FIG. If it is desired to start fuel injection in the cylinder # 2 where injection is performed, a crank angle Ca of 360 ° or more is required before the fuel injection timing in order to ensure that the number of pumps of the high-pressure pump 5 is 1.5. Displacement is required. Further, as in the example of FIG. 5B, if it is desired to start fuel injection in cylinder # 1 where fuel injection is performed at a position where the plunger 7 is at the top dead center (crank angle 720 °), the high-pressure pump 5 In order to ensure that the number of pumping times is 1.5, the crank angle Ca must be displaced by 300 ° or more before the fuel injection timing.
　また、図６（ａ）の例のように、プランジャ７が上昇途中にある位置（クランク角９００°）で燃料噴射が行われる気筒♯３で燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、その燃料噴射タイミングまでに３００°以上のクランク角Caの変位が必要となる。さらに、図６（ｂ）の例のように、プランジャ７が下死点にある位置（クランク角３６０°）で燃料噴射が行われる気筒♯４で燃料噴射を開始したいとすると、高圧ポンプ５の圧送回数が１．５圧送確保されるようにするためには、その燃料噴射タイミングまでに４２０°以上のクランク角Caの変位が必要となる。 Further, as in the example of FIG. 6A, if it is desired to start fuel injection in cylinder # 3 where fuel injection is performed at a position where the plunger 7 is in the middle of raising (crank angle 900 °), the high-pressure pump 5 pumps the fuel. In order to ensure that the number of times is 1.5, the crank angle Ca must be displaced by 300 ° or more before the fuel injection timing. Furthermore, as in the example of FIG. 6B, if it is desired to start fuel injection in cylinder # 4 where fuel injection is performed at a position where the plunger 7 is at the bottom dead center (crank angle 360 °), the high-pressure pump 5 In order to ensure that the number of pumping times is 1.5, the crank angle Ca must be displaced by 420 ° or more before the fuel injection timing.
　このように、それぞれの燃料噴射タイミングにおける高圧燃料の正常噴射が可能となる高圧ポンプ５の最大圧送回数を確保するために必要とされるクランク角Caの変位は、燃料噴射タイミングや必要とされる高圧ポンプ５の最大圧送回数によって異なる。そのため、ディーゼルエンジン４０の停止時のクランク角Caと、必要とされるクランク角Caの変位とに基づき、クランク角Caをずらす量が最小となるように目標位置Catgtが設定されてクランク角Caがずらされる。 As described above, the displacement of the crank angle Ca required to ensure the maximum number of pumping times of the high-pressure pump 5 that enables normal injection of high-pressure fuel at each fuel injection timing is required for the fuel injection timing and the like. It depends on the maximum number of pumping times of the high-pressure pump 5. Therefore, based on the crank angle Ca when the diesel engine 40 is stopped and the required displacement of the crank angle Ca, the target position Catgt is set so that the amount of shifting the crank angle Ca is minimized, and the crank angle Ca is It is shifted.
　その結果、クランク角Caを目標位置Catgtにずらす量が小さく済み、バッテリーやスタータ４４への負荷が低減される。そして、バッテリーの負荷が低減されることで、次回のドライビングサイクル中にオルタネータが発電すべき電力量が減少するために、オルタネータの作動に必要なトルクが減少するとともに、燃費の向上も図られる。また、再始動条件が成立してからクランク角Caをずらすのであれば、クランク角Caをずらすための時間も短縮できるために、ディーゼルエンジン４０を速やかに再始動させることができる。 As a result, the amount of shifting the crank angle Ca to the target position Catgt is small, and the load on the battery and the starter 44 is reduced. Since the load of the battery is reduced, the amount of power that the alternator should generate during the next driving cycle is reduced, so that the torque required for the operation of the alternator is reduced and the fuel efficiency is improved. Further, if the crank angle Ca is shifted after the restart condition is established, the time for shifting the crank angle Ca can be shortened, so that the diesel engine 40 can be restarted quickly.
　なお、本実施形態の説明に用いられている蓄圧式燃料噴射装置５０は、低圧ポンプとして電動低圧ポンプ２を備えていることから、ディーゼルエンジン４０が停止状態であっても高圧ポンプ５に供給される低圧燃料の流量を確保することができる。そのため、図３～図６のいずれの蓄圧式燃料噴射装置の例においても、クランク角Caをずらすにあたり、クランクシャフト４３を進角させることも退角させることもできるようになっている。 The accumulator fuel injection device 50 used in the description of the present embodiment includes the electric low-pressure pump 2 as a low-pressure pump, and thus is supplied to the high-pressure pump 5 even when the diesel engine 40 is stopped. The flow rate of low-pressure fuel can be secured. Therefore, in any of the pressure-accumulation fuel injection devices in FIGS. 3 to 6, the crankshaft 43 can be advanced or retracted when the crank angle Ca is shifted.
（２）レール圧が噴射可能圧力以上のままで維持されたときの制御（制御モード２）
　本実施形態の制御装置７０において、アイドリングストップ制御によるディーゼルエンジン４０の停止中にレール圧Prが噴射可能圧力Pr0以上のままで維持されている場合には、高圧ポンプ５のプランジャ７の位置にかかわらず、ディーゼルエンジン４０の特性に応じて必要とされる圧縮行程が燃料噴射前に行われるようにクランク角Caがずらされる。この場合には、すでに高圧燃料の正常噴射が可能な状態であることから、所定ストローク分の圧縮行程が行われた後燃料が噴射され、速やかにディーゼルエンジン４０が再始動する。 (2) Control when the rail pressure is maintained above the injectable pressure (control mode 2)
In the control device 70 of the present embodiment, when the rail pressure Pr is maintained at or above the injectable pressure Pr0 while the diesel engine 40 is stopped by the idling stop control, the position is related to the position of the plunger 7 of the high-pressure pump 5. Instead, the crank angle Ca is shifted so that the compression stroke required according to the characteristics of the diesel engine 40 is performed before fuel injection. In this case, since the normal injection of the high-pressure fuel is already possible, the fuel is injected after the compression stroke for a predetermined stroke is performed, and the diesel engine 40 is restarted promptly.
　具体的に、ディーゼルエンジン４０では各気筒において吸気行程、圧縮行程、爆発行程及び排気行程が繰り返され、圧縮行程において燃料噴射が行われる。ディーゼルエンジン４０の再始動条件成立時にレール圧Prが噴射可能圧力Pr0以上になっており、高圧燃料の正常噴射が可能な状態である場合には、次回燃料噴射タイミングが到来する気筒を検出し、この気筒において、所定ストローク分の圧縮行程が行われるようなクランク角Caからクランキングが開始されるようにクランク角Caの目標位置Catgtが設定される。燃料噴射前の必要な圧縮行程はディーゼルエンジン４０ごとに試験等によってあらかじめ求められる。 Specifically, in the diesel engine 40, the intake stroke, the compression stroke, the explosion stroke, and the exhaust stroke are repeated in each cylinder, and fuel injection is performed in the compression stroke. When the restart condition of the diesel engine 40 is satisfied, the rail pressure Pr is equal to or higher than the injectable pressure Pr0, and when normal injection of high-pressure fuel is possible, the cylinder at which the next fuel injection timing comes is detected, In this cylinder, the target position Catgt of the crank angle Ca is set so that cranking starts from the crank angle Ca at which a compression stroke for a predetermined stroke is performed. The required compression stroke before fuel injection is obtained in advance for each diesel engine 40 by a test or the like.
　図７は、一つの気筒におけるピストンのリフト位置とディーゼルエンジン４０のクランク角Caとの関係を示している。この図７では、クランク角Caが圧縮行程の終期に近い７１０°の時点に燃料噴射タイミングが設定されている。試験等によってあらかじめ求められた燃料噴射前の必要な圧縮行程が、例えば１００°分のクランク角Caの変位であれば、クランク角Caをずらす目標位置Catgtは６１０°に設定される。また、若干の吸気行程を含む方が良いのであれば、クランク角Caをずらす目標位置Catgtは例えば５２０°に設定され、吸気行程からクランキングが開始されるようにする。その結果、クランキングの開始以降必要な行程を経たうえで気筒４１内に燃料が噴射されるために、ディーゼルエンジン４０が速やかに再始動する。 FIG. 7 shows the relationship between the piston lift position and the crank angle Ca of the diesel engine 40 in one cylinder. In FIG. 7, the fuel injection timing is set at a time when the crank angle Ca is 710 °, which is close to the end of the compression stroke. If the required compression stroke before fuel injection obtained in advance by testing or the like is, for example, a displacement of the crank angle Ca by 100 °, the target position Catgt for shifting the crank angle Ca is set to 610 °. If it is better to include a slight intake stroke, the target position Catgt for shifting the crank angle Ca is set to 520 °, for example, and cranking is started from the intake stroke. As a result, since the fuel is injected into the cylinder 41 after a necessary stroke after the start of cranking, the diesel engine 40 is quickly restarted.
４．ディーゼルエンジンの制御方法
　次に、本実施形態のディーゼルエンジン４０の制御装置７０によって実行されるディーゼルエンジン４０の制御方法の一例について、図８に示す制御フローに基づき具体的に説明する。 4). Next, an example of a control method of the diesel engine 40 executed by the control device 70 of the diesel engine 40 of the present embodiment will be specifically described based on the control flow shown in FIG.
　ディーゼルエンジン４０の運転中において、まず、ステップＳ１で、ディーゼルエンジン４０の回転数Ne、アクセルペダルの操作量Acc、ブレーキペダルの操作量Brk、変速機のクラッチ位置Cp、変速機のシフト位置Gpが読込まれる。次いで、ステップＳ２で、ステップＳ１で読み込まれたセンサ値等の情報に基づき、あらかじめ設定されたアイドリングストップ条件が成立しているか否かが判別される。アイドリングストップ条件が成立するまでステップＳ１及びステップＳ２が繰り返される。 During operation of the diesel engine 40, first, in step S1, the rotational speed Ne of the diesel engine 40, the accelerator pedal operation amount Acc, the brake pedal operation amount Brk, the transmission clutch position Cp, and the transmission shift position Gp are determined. Read. Next, in step S2, it is determined whether or not a preset idling stop condition is satisfied based on the information such as the sensor value read in step S1. Steps S1 and S2 are repeated until the idling stop condition is satisfied.
　アイドリングストップ条件が成立すると、ステップＳ３で、燃料噴射を停止してディーゼルエンジン４０が停止されるとともに、ステップＳ４でディーゼルエンジン４０停止時のクランク角Caが検出され記憶される。さらに、ステップＳ５で、制御装置７０に記憶されている情報に基づき、次に燃料噴射タイミングが到来する気筒（燃料噴射弁）が検出される。 When the idling stop condition is satisfied, the fuel injection is stopped and the diesel engine 40 is stopped in step S3, and the crank angle Ca when the diesel engine 40 is stopped is detected and stored in step S4. Furthermore, in step S5, based on the information stored in the control device 70, the cylinder (fuel injection valve) from which the fuel injection timing comes next is detected.
　次いで、ステップＳ６ではレール圧Prが検出され、さらに、ステップＳ７で検出されたレール圧Prが噴射可能圧力Pr0未満となったか否かが判別される。ステップＳ７において、レール圧Prが噴射可能圧力Pr0未満になった場合には、制御モード１のクランク角ずらし制御を行うステップＳ８に進む一方、レール圧Prが噴射可能圧力Pr0以上の場合には、制御モード２のクランク角ずらし制御を行うステップＳ１４に進む。 Next, in step S6, the rail pressure Pr is detected, and it is further determined whether or not the rail pressure Pr detected in step S7 is less than the injectable pressure Pr0. In step S7, when the rail pressure Pr becomes less than the injectable pressure Pr0, the process proceeds to step S8 in which the crank angle shift control in the control mode 1 is performed. On the other hand, when the rail pressure Pr is equal to or higher than the injectable pressure Pr0, The process proceeds to step S14 where the crank angle shift control in the control mode 2 is performed.
　制御モード１のクランク角ずらし制御を行うステップＳ８に進むと、次のステップＳ９で、ステップＳ４において検出されたディーゼルエンジン４０停止時のクランク角Caと、ステップＳ５において検出された次に燃料噴射タイミングが到来する気筒の情報と、あらかじめ記憶されている各気筒ごとに高圧燃料の正常噴射を可能とするために必要なクランク角Caの変位とに基づき、クランク角Caをずらす目標位置Catgtが設定される。次いで、ステップＳ１０では、ステップＳ９で設定された目標位置Catgtに従い、スタータ４４に指示が出力され、ディーゼルエンジン４０の再始動後にレール圧Prが速やかに噴射可能圧力Pr0以上に到達するような位置にクランク角Caがずらされる。 When the process proceeds to step S8 where the crank angle shift control in the control mode 1 is performed, in the next step S9, the crank angle Ca when the diesel engine 40 is stopped detected in step S4, and the next fuel injection timing detected in step S5. The target position Catgt for shifting the crank angle Ca is set on the basis of the information on the cylinder in which the air pressure arrives and the displacement of the crank angle Ca necessary to enable normal injection of high-pressure fuel for each cylinder stored in advance. The Next, in step S10, in accordance with the target position Catgt set in step S9, an instruction is output to the starter 44, and the rail pressure Pr quickly reaches the injectable pressure Pr0 or more after the diesel engine 40 is restarted. The crank angle Ca is shifted.
　クランク角がずらされた後は、ステップＳ１１に進みアクセルペダルの操作量Acc、ブレーキペダルの操作量Brk、変速機のクラッチ位置Cp、変速機のシフト位置Gp等が読込まれるとともに、ステップＳ１２でエンジン再始動条件が成立しているか否かが判別される。エンジン再始動条件が成立するまでこのステップＳ１１～ステップＳ１２が繰り返され、エンジン再始動条件が成立したときにステップＳ１３に進み、ディーゼルエンジン４０のクランキングが開始されて、ディーゼルエンジン４０が速やかに始動する。
　なお、クランク角CaをずらすステップＳ１０は、エンジン再始動条件が成立したステップＳ１２の後に実施されてもよい。 After the crank angle is shifted, the routine proceeds to step S11, where the accelerator pedal operation amount Acc, the brake pedal operation amount Brk, the transmission clutch position Cp, the transmission shift position Gp, etc. are read, and at step S12. It is determined whether or not an engine restart condition is satisfied. Steps S11 to S12 are repeated until the engine restart condition is satisfied. When the engine restart condition is satisfied, the process proceeds to step S13, cranking of the diesel engine 40 is started, and the diesel engine 40 is quickly started. To do.
Note that step S10 for shifting the crank angle Ca may be performed after step S12 when the engine restart condition is satisfied.
　一方、ステップＳ６においてレール圧Prが噴射可能圧力Pr0以上の場合に、制御モード２のクランク角ずらし制御を行うステップＳ１４に進むと、次のステップＳ１５においてアクセルペダルの操作量Acc、ブレーキペダルの操作量Brk、変速機のクラッチ位置Cp、変速機のシフト位置Gp等が読込まれるとともに、ステップＳ１６でエンジン再始動条件が成立しているか否かが判別される。エンジン再始動条件が成立していない場合には、ステップＳ６に戻り、これまでと同様のステップが行われる。 On the other hand, when the rail pressure Pr is equal to or higher than the injectable pressure Pr0 in step S6, the process proceeds to step S14 where the crank angle shift control in the control mode 2 is performed. In the next step S15, the accelerator pedal operation amount Acc and the brake pedal operation The amount Brk, the transmission clutch position Cp, the transmission shift position Gp, and the like are read, and it is determined in step S16 whether or not an engine restart condition is satisfied. If the engine restart condition is not satisfied, the process returns to step S6, and the same steps as before are performed.
　ステップＳ１６においてエンジン再始動条件が成立している場合には、エンジン再始動条件成立時までレール圧Prが噴射可能圧力Pr0以上のままで維持されていたことになるため、ステップＳ１７に進み、ステップＳ５において検出された次に燃料噴射タイミングが到来する気筒において、あらかじめ記憶された、燃料噴射前に必要な圧縮行程が確保されるクランク角Caからクランキングが再開されるような位置に目標位置Catgtが設定される。そして、ステップＳ１８でステップＳ１７で設定された目標位置Catgtに従いスタータ４４に指示が出力され、クランク角Caがずらされる。制御モード２でクランク角ずらし制御が実行された後は、ステップＳ１３に進み、ディーゼルエンジン４０のクランキングが開始されて、ディーゼルエンジン４０が速やかに始動する。
　なお、エンジン再始動条件成立の有無を判定するステップＳ１６を実施する前に、あらかじめステップＳ１７～Ｓ１８が実施されてもよい。 If the engine restart condition is satisfied in step S16, the rail pressure Pr is maintained at or above the injectable pressure Pr0 until the engine restart condition is satisfied. In the cylinder where the fuel injection timing comes next detected in S5, the target position Catgt is set at a position stored in advance so that cranking is restarted from the crank angle Ca at which the necessary compression stroke is ensured before fuel injection. Is set. In step S18, an instruction is output to the starter 44 in accordance with the target position Catgt set in step S17, and the crank angle Ca is shifted. After the crank angle shifting control is executed in the control mode 2, the process proceeds to step S13, cranking of the diesel engine 40 is started, and the diesel engine 40 is started quickly.
Note that steps S17 to S18 may be performed in advance before performing step S16 for determining whether or not the engine restart condition is satisfied.
　ここまで説明した制御方法の例では、アイドリングストップ制御によるディーゼルエンジン４０の停止中にレール圧Prが噴射可能圧力Pr0未満になったときに、クランク角Caがあらかじめ設定された所定の位置にずらされるようになっている。制御装置７０が、ディーゼルエンジン４０の再始動時のレール圧Prと噴射可能圧力Pr0との差から高圧ポンプ５による必要圧送回数を演算可能に構成されている場合には、アイドリングストップ制御によるディーゼルエンジン４０の停止後エンジン再始動条件が成立したときに、レール圧Prを検出するとともに高圧ポンプ５の必要圧送回数を算出し、この必要圧送回数に応じてクランク角をずらす目標位置を決定して、クランク角ずらし制御を行うようにしてもよい。 In the example of the control method described so far, when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine 40 is stopped by the idling stop control, the crank angle Ca is shifted to a predetermined position set in advance. It is like that. When the control device 70 is configured to be able to calculate the required number of pumping times by the high-pressure pump 5 from the difference between the rail pressure Pr and the injectable pressure Pr0 when the diesel engine 40 is restarted, the diesel engine by idling stop control When the engine restart condition after the stop of 40 is established, the rail pressure Pr is detected and the required number of pumping times of the high pressure pump 5 is calculated, and the target position for shifting the crank angle is determined according to the required number of pumping times, Crank angle shifting control may be performed.
［第２の実施の形態］
　本発明の第２の実施の形態は、蓄圧式燃料噴射装置に備えられる低圧ポンプとして、ギヤポンプ等のディーゼルエンジンの回転状態に依存したポンプが用いられている場合の例である。
　低圧ポンプが、例えばギヤポンプである場合、ギヤポンプはディーゼルエンジンのクランクシャフトに連結されている。そのため、低圧ポンプの駆動力はディーゼルエンジンの回転状態に依存し、ディーゼルエンジンの停止状態においては高圧ポンプの加圧室に低圧燃料の供給が行われない。さらに、ディーゼルエンジンの始動前にクランク角をずらすにあたり、クランクシャフトを退角させた場合には、高圧ポンプのプランジャの上下動にかかわらず加圧室に燃料が供給されない。 [Second Embodiment]
The second embodiment of the present invention is an example in the case where a pump that depends on the rotational state of a diesel engine such as a gear pump is used as a low-pressure pump provided in an accumulator fuel injection device.
When the low-pressure pump is a gear pump, for example, the gear pump is connected to the crankshaft of the diesel engine. Therefore, the driving force of the low-pressure pump depends on the rotational state of the diesel engine, and low-pressure fuel is not supplied to the pressurizing chamber of the high-pressure pump when the diesel engine is stopped. Furthermore, when the crankshaft is retreated to shift the crank angle before starting the diesel engine, fuel is not supplied to the pressurizing chamber regardless of the vertical movement of the plunger of the high-pressure pump.
　そのため、本実施形態の制御装置のクランク角制御部は、ディーゼルエンジンの停止中にレール圧が噴射可能圧力未満になった時に、高圧燃料の正常噴射が可能な圧力にレール圧が到達するために必要な高圧ポンプの最大圧送回数が確保されるように、高圧ポンプが燃料吸入行程にある状態を目標位置としてクランク角をずらす制御を行うように構成されている。 For this reason, the crank angle control unit of the control device of the present embodiment causes the rail pressure to reach the pressure at which normal injection of high-pressure fuel can be performed when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped. In order to ensure the required maximum number of pumping times of the high-pressure pump, control is performed to shift the crank angle with the high-pressure pump in the fuel intake stroke as a target position.
　本実施形態の制御装置も、第１の実施の形態の制御装置と同様に、アイドリングストップ制御によるディーゼルエンジンの停止中にレール圧Prが噴射可能圧力Pr0未満になった時には、再始動時にレール圧Prが速やかに噴射可能圧力Pr0以上に到達するようにクランク角Caがずらされる（制御モード１）。また、本実施形態の制御装置は、ディーゼルエンジンの停止中でもレール圧Prが噴射可能圧力Pr0以上に維持されている場合には、再始動時に燃料噴射前に必要な分の圧縮行程が行われる位置からクランキングが開始されるようにクランク角Caがずらされる（制御モード２）。 Similarly to the control device of the first embodiment, when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine is stopped by the idling stop control, the control device of the present embodiment also has a rail pressure at the time of restart. The crank angle Ca is shifted so that Pr quickly reaches the injectable pressure Pr0 or more (control mode 1). In addition, the control device of the present embodiment is a position where the compression stroke necessary for fuel injection is performed at the time of restart when the rail pressure Pr is maintained at the injectable pressure Pr0 or higher even when the diesel engine is stopped. The crank angle Ca is shifted so that cranking starts from (control mode 2).
　このうち、ディーゼルエンジンの停止中でもレール圧Prが噴射可能圧力Pr0以上に維持されている場合に行われる制御モード２は、第１の実施の形態で説明した内容と同様である。一方、アイドリングストップ制御によるディーゼルエンジンの停止中にレール圧Prが噴射可能圧力Pr0未満になった時に行われる制御モード１は、第１の実施の形態と異なるため、以下、制御モード１について詳細に説明する。 Among these, the control mode 2 performed when the rail pressure Pr is maintained at the injectable pressure Pr0 or higher even when the diesel engine is stopped is the same as the content described in the first embodiment. On the other hand, the control mode 1 performed when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine is stopped by the idling stop control is different from the first embodiment. explain.
　図９は、ディーゼルエンジンの停止中にレール圧Prが噴射可能圧力Pr0未満になった時に実行されるクランク角の調節方法を説明するための図であって、第１の実施の形態で説明した図３に相当する図である。この図９の例は、第１の実施の形態と同様、レール圧Prを大気圧から噴射可能圧力Pr0以上にするまでに高圧ポンプからの圧送回数が最大１．５圧送必要な蓄圧式燃料噴射装置の例である。図９において、プランジャのリフト位置が増大している行程が燃料圧送行程を表し、プランジャのリフト量が減少している行程が燃料吸入行程を表している。 FIG. 9 is a diagram for explaining a crank angle adjustment method executed when the rail pressure Pr becomes less than the injectable pressure Pr0 while the diesel engine is stopped, and is described in the first embodiment. FIG. 4 is a diagram corresponding to FIG. 3. In the example of FIG. 9, as in the first embodiment, the accumulator fuel injection that requires a maximum of 1.5 pumping cycles from the high pressure pump until the rail pressure Pr is changed from the atmospheric pressure to the injectable pressure Pr0 or more. It is an example of an apparatus. In FIG. 9, a stroke in which the lift position of the plunger is increased represents a fuel pressure feed stroke, and a stroke in which the lift amount of the plunger is decreased represents a fuel intake stroke.
　低圧ポンプがディーゼルエンジンの回転状態に依存するポンプである場合、ディーゼルエンジンの停止中においては高圧ポンプの加圧室に低圧燃料が供給されることがない。そのため、単純に高圧ポンプからの必要圧送回数分の燃料圧送行程が行われるように、高圧ポンプの燃料圧送行程中にクランク角Caの目標位置Catgtを設定したとしても、コモンレールへの高圧燃料の圧送量が確保できないおそれがある。 When the low pressure pump is a pump that depends on the rotational state of the diesel engine, the low pressure fuel is not supplied to the pressurizing chamber of the high pressure pump while the diesel engine is stopped. Therefore, even if the target position Catgt of the crank angle Ca is set during the fuel pumping stroke of the high-pressure pump so that the fuel pumping stroke of the required number of pumping times from the high-pressure pump is simply performed, the high-pressure fuel pumping to the common rail is performed. The amount may not be secured.
　すなわち、図９の例において、プランジャが上死点にあるクランク角Caが５４０°の時点で燃料噴射を開始させるために、高圧ポンプの燃料圧送行程が１．５回分確保されるように、クランク角Caが３１５°の位置からクランキングを開始させたとしても、クランキング開始時の高圧ポンプの加圧室内への低圧燃料の吸入が十分でない場合には、コモンレールへの高圧燃料の圧送量が不足する。その結果、レール圧が高圧燃料の正常噴射が可能な圧力に到達しなくなる。 That is, in the example of FIG. 9, in order to start fuel injection when the crank angle Ca at which the plunger is at the top dead center is 540 °, the crank pressure is secured so that the fuel pumping stroke of the high-pressure pump is 1.5 times. Even if the cranking is started from the position where the angle Ca is 315 °, if the suction of the low-pressure fuel into the pressurizing chamber of the high-pressure pump at the start of cranking is not sufficient, the pumping amount of the high-pressure fuel to the common rail is Run short. As a result, the rail pressure does not reach a pressure at which normal injection of high-pressure fuel is possible.
　そのため、本実施形態のような、ディーゼルエンジンの回転状態に依存して駆動される低圧ポンプが用いられる場合には、高圧ポンプからの最大圧送回数分の低圧燃料が高圧ポンプの加圧室に吸入されるように、高圧ポンプが燃料吸入行程にある状態を目標位置としてクランク角Caがずらされる。クランキング開始から燃料噴射タイミングまでに必要な回数の燃料吸入行程が行われるようにクランク角Caの目標位置Catgtが設定されるため、クランク角Caをずらす際の進退方向はどちらでも構わない。図９の例において、プランジャが上死点にあるクランク角Caが５４０°の時点で燃料噴射を開始させるためには、クランキング開始時点から燃料噴射タイミングまでに燃料吸入行程が１．５回分確保されるように、クランク角Caをずらす目標位置Catgtが２２５°に設定される。 Therefore, when a low-pressure pump that is driven depending on the rotational state of the diesel engine is used as in this embodiment, low-pressure fuel for the maximum number of pumping times from the high-pressure pump is sucked into the pressurization chamber of the high-pressure pump. As described above, the crank angle Ca is shifted with the state where the high-pressure pump is in the fuel intake stroke as the target position. Since the target position Catgt of the crank angle Ca is set so that the required number of fuel intake strokes from the start of cranking to the fuel injection timing are performed, the forward / backward direction when shifting the crank angle Ca may be either. In the example of FIG. 9, in order to start fuel injection when the crank angle Ca at which the plunger is at the top dead center is 540 °, the fuel intake stroke is secured 1.5 times from the cranking start time to the fuel injection timing. Thus, the target position Catgt for shifting the crank angle Ca is set to 225 °.
　具体的に、アイドリングストップ制御によってクランク角Caが４５０°のＡの位置でディーゼルエンジンが停止したとする。このとき、次に燃料噴射タイミングが到来する気筒♯２から燃料噴射を開始したいとすると、燃料噴射タイミングまでに燃料吸入行程が１．５回分確保されるようにするためには、クランク角Caの目標位置Catgtを２２５°に設定して、クランク角Caを－２２５°ずらす必要がある。また、その次に燃料噴射タイミングが到来する気筒♯１から燃料噴射を開始したいとすると、燃料噴射タイミングまでに燃料吸入行程が１．５回分確保されるようにするためには、クランク角Caの目標位置Catgtを４０５°に設定して、クランク角Caを－４５°ずらす必要がある。さらに、気筒♯３から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを５８５°に設定してクランク角Caを＋１３５°ずらす必要があり、気筒♯４から燃料噴射を開始したいとするとクランク角Caの目標位置Catgtを７６５°に設定してクランク角Caを＋３１５°ずらす必要がある。 Specifically, it is assumed that the diesel engine is stopped at a position where the crank angle Ca is 450 ° by the idling stop control. At this time, if it is desired to start fuel injection from the cylinder # 2 at which the next fuel injection timing comes, in order to secure 1.5 fuel intake strokes by the fuel injection timing, the crank angle Ca It is necessary to set the target position Catgt to 225 ° and shift the crank angle Ca by −225 °. Further, if it is desired to start fuel injection from the cylinder # 1 at which the fuel injection timing comes next, in order to secure 1.5 fuel intake strokes by the fuel injection timing, the crank angle Ca It is necessary to set the target position Catgt to 405 ° and shift the crank angle Ca by −45 °. Further, if it is desired to start fuel injection from cylinder # 3, it is necessary to set the target position Catgt of crank angle Ca to 585 ° and shift crank angle Ca by + 135 °, and if it is desired to start fuel injection from cylinder # 4, crank It is necessary to set the target position Catgt of the angle Ca to 765 ° and shift the crank angle Ca by + 315 °.
　このうち、クランク角Caをずらす量が最小となるのは気筒♯１から燃料噴射を開始する場合であるため、クランク角Caの目標位置Catgt(A)が４０５°に設定されて、ディーゼルエンジンの再始動時までにクランク角Caがずらされる。その結果、クランク角Caをずらす時間が最短になってクランク角Caをずらす負荷が低減されるとともに、ディーゼルエンジンの再始動時にクランキングを開始させてから短時間での高圧燃料の正常噴射が可能になる。 Of these, the amount of shift of the crank angle Ca is minimized when fuel injection is started from the cylinder # 1, so the target position Catgt (A) of the crank angle Ca is set to 405 °, and the diesel engine The crank angle Ca is shifted by the time of restart. As a result, the time to shift the crank angle Ca is minimized, the load to shift the crank angle Ca is reduced, and normal injection of high-pressure fuel is possible in a short time after cranking is started when the diesel engine is restarted become.
　この他、それぞれの燃料噴射タイミングにおける高圧燃料の正常噴射が可能となる高圧ポンプ５の最大圧送回数分の燃料吸入行程を確保するために必要とされるクランク角Caの変位は、燃料噴射タイミングや必要とされる高圧ポンプ５の最大圧送回数によって異なる。そのため、ディーゼルエンジンの停止時のクランク角Caと、必要回数の燃料吸入行程が確保されるクランキングの開始位置とに基づき、クランク角Caをずらす量が最小となるように目標位置Catgtが設定されてクランク角Caがずらされる。 In addition, the displacement of the crank angle Ca required to secure the fuel intake stroke for the maximum number of pumping times of the high-pressure pump 5 that enables normal injection of high-pressure fuel at each fuel injection timing is the fuel injection timing or It differs depending on the required maximum number of pumping times of the high-pressure pump 5. Therefore, the target position Catgt is set so that the amount by which the crank angle Ca is shifted is minimized based on the crank angle Ca when the diesel engine is stopped and the cranking start position at which the required number of fuel intake strokes are secured. As a result, the crank angle Ca is shifted.
　その結果、クランク角Caを目標位置Catgtにずらす量が小さく済み、バッテリーやスタータへの負荷が低減される。また、再始動条件が成立してからクランク角Caをずらすのであれば、クランク角Caをずらすための時間も短縮できるために、ディーゼルエンジンを速やかに再始動させることができる。 As a result, the amount of shifting the crank angle Ca to the target position Catgt is small, and the load on the battery and starter is reduced. In addition, if the crank angle Ca is shifted after the restart condition is satisfied, the time for shifting the crank angle Ca can be shortened, so that the diesel engine can be restarted quickly.
　以上説明した本実施形態のディーゼルエンジンの制御方法によれば、アイドリングストップ制御によるディーゼルエンジンの停止中に、レール圧が噴射可能圧力未満になったときには、エンジン再始動条件が成立し、ディーゼルエンジンのクランキングが開始されたときにレール圧が速やかに噴射可能圧力に到達するようにクランク角がずらされる。一方、ディーゼルエンジンの停止中、エンジン再始動条件が成立するまでレール圧が噴射可能圧力以上に維持されていたときには、燃料噴射前に必要な分の圧縮行程が行われる位置からクランキングが開始されるようにクランク角がずらされる。したがって、エンジン再始動条件成立時のレール圧の状態に応じて、速やかにディーゼルエンジンを再始動させることが可能になる。 According to the diesel engine control method of the present embodiment described above, the engine restart condition is satisfied when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped by the idling stop control. The crank angle is shifted so that the rail pressure quickly reaches the injectable pressure when cranking is started. On the other hand, when the diesel engine is stopped, if the rail pressure is maintained above the injectable pressure until the engine restart condition is satisfied, cranking is started from the position where the necessary compression stroke is performed before fuel injection. The crank angle is shifted as shown. Therefore, the diesel engine can be restarted promptly according to the rail pressure state when the engine restart condition is satisfied.

Claims (9)

  1. 　高圧ポンプと、前記高圧ポンプで加圧された燃料が蓄積されるコモンレールと、前記コモンレールに接続され前記燃料をディーゼルエンジンの気筒内に噴射する複数の燃料噴射弁と、を有する蓄圧式燃料噴射装置を備えたディーゼルエンジンの制御を行うためのディーゼルエンジンの制御装置において、
    　所定のアイドリングストップ条件が成立したときに前記ディーゼルエンジンを停止させるとともに、所定の再始動条件が成立したときに前記ディーゼルエンジンを再始動させる制御を行うアイドリングストップ制御部と、
    　前記ディーゼルエンジンの停止中に、前記ディーゼルエンジンの再始動時に前記コモンレール内の圧力が高圧燃料の正常噴射が可能な圧力以上に速やかに到達するように前記ディーゼルエンジンのクランク角をずらす制御を行うクランク角制御部と、
    　を備えることを特徴とするディーゼルエンジンの制御装置。     An accumulator fuel injection device comprising: a high-pressure pump; a common rail that stores fuel pressurized by the high-pressure pump; and a plurality of fuel injection valves that are connected to the common rail and inject the fuel into a cylinder of a diesel engine In a diesel engine control device for controlling a diesel engine equipped with
    An idling stop control unit that performs control to stop the diesel engine when a predetermined idling stop condition is satisfied, and to restart the diesel engine when a predetermined restart condition is satisfied;
    A crank that controls the shift of the crank angle of the diesel engine so that the pressure in the common rail quickly reaches a pressure that allows normal injection of high-pressure fuel when the diesel engine is restarted while the diesel engine is stopped. An angle control unit;
    A control device for a diesel engine, comprising:
  2. 　前記クランク角制御部は、前記コモンレール内の圧力を前記高圧燃料の正常噴射が可能な圧力以上にするために必要な前記高圧ポンプの最大圧送回数に応じて、前記クランク角をずらす目標位置を決定することを特徴とする請求項１に記載のディーゼルエンジンの制御装置。 The crank angle control unit determines a target position to shift the crank angle according to the maximum number of pumping times of the high pressure pump necessary to make the pressure in the common rail equal to or higher than the pressure at which the high pressure fuel can be normally injected. The diesel engine control device according to claim 1, wherein the control device is a diesel engine control device.
  3. 　前記クランク角制御部は、再始動時の燃料噴射タイミングでの高圧ポンプのプランジャのリフト位置に応じて、前記クランク角をずらす目標位置を決定することを特徴とする請求項１又は２に記載のディーゼルエンジンの制御装置。 The said crank angle control part determines the target position which shifts the said crank angle according to the lift position of the plunger of a high-pressure pump in the fuel injection timing at the time of restart. Diesel engine control device.
  4. 　前記クランク角制御部は、前記ディーゼルエンジンの再始動時に前記コモンレール内の圧力が前記高圧燃料の正常噴射が可能な圧力以上に速やかに到達するクランク角の目標位置を前記複数の燃料噴射弁ごとにそれぞれ演算するとともに、それぞれ算出された複数の前記目標位置のうち、前記クランク角をずらす量が最小となる前記目標位置に前記クランク角をずらすことを特徴とする請求項１～３のいずれか一項に記載のディーゼルエンジンの制御装置。 For each of the plurality of fuel injection valves, the crank angle control unit determines a crank angle target position at which the pressure in the common rail quickly reaches the pressure at which normal injection of the high-pressure fuel can be achieved when the diesel engine is restarted. The crank angle is shifted to the target position where the amount of shifting the crank angle is minimized among the plurality of calculated target positions, respectively. The control apparatus of the diesel engine as described in a term.
  5. 　前記高圧ポンプに燃料を供給する低圧ポンプが前記ディーゼルエンジンの回転状態に依存せずに駆動されるポンプである場合には、前記クランク角制御部は前記高圧ポンプが燃料圧送行程にある状態を目標位置として前記クランク角を進角又は退角させる制御を行うことを特徴とする請求項１～４のいずれか一項に記載のディーゼルエンジンの制御装置。 When the low-pressure pump that supplies fuel to the high-pressure pump is a pump that is driven without depending on the rotational state of the diesel engine, the crank angle control unit targets the state in which the high-pressure pump is in the fuel pressure stroke. The diesel engine control device according to any one of claims 1 to 4, wherein control is performed to advance or retreat the crank angle as a position.
  6. 　前記高圧ポンプに燃料を供給する低圧ポンプが前記ディーゼルエンジンの回転状態に依存して駆動されるポンプである場合には、前記クランク角制御部は前記高圧ポンプの最大圧送回数が確保されるように前記高圧ポンプが燃料吸入行程にある状態を前記目標位置として前記クランク角を進角又は退角させる制御を行うことを特徴とする請求項１～４のいずれか一項に記載のディーゼルエンジンの制御装置。 When the low-pressure pump that supplies fuel to the high-pressure pump is a pump that is driven depending on the rotational state of the diesel engine, the crank angle control unit ensures that the maximum number of pumping times of the high-pressure pump is ensured. The control of the diesel engine according to any one of claims 1 to 4, wherein the control is performed to advance or retreat the crank angle with the high pressure pump being in a fuel intake stroke as the target position. apparatus.
  7. 　前記ディーゼルエンジンの制御装置は、前記コモンレール内の圧力を検出するレール圧検出部を備え、
    　前記クランク角制御部は、前記再始動条件成立時に検出される前記コモンレール内の圧力と、前記高圧燃料の正常噴射が可能な圧力との差に基づき、前記クランク角をずらす目標位置を決定することを特徴とする請求項１～６のいずれか一項に記載のディーゼルエンジンの制御装置。     The control device for the diesel engine includes a rail pressure detection unit that detects a pressure in the common rail,
    The crank angle control unit determines a target position for shifting the crank angle based on a difference between a pressure in the common rail detected when the restart condition is satisfied and a pressure at which the high pressure fuel can be normally injected. The diesel engine control device according to any one of claims 1 to 6, wherein:
  8. 　前記ディーゼルエンジンの制御装置は、前記コモンレール内の圧力を検出するレール圧検出部を備え、
    　前記クランク角制御部は、前記ディーゼルエンジンの停止中に前記コモンレール内の圧力が前記高圧燃料の正常噴射が可能な圧力未満になったときに、前記クランク角をずらす制御を行うことを特徴とする請求項１～７のいずれか一項に記載のディーゼルエンジンの制御装置。     The control device for the diesel engine includes a rail pressure detection unit that detects a pressure in the common rail,
    The crank angle control unit performs control to shift the crank angle when the pressure in the common rail becomes less than a pressure at which the high pressure fuel can be normally injected while the diesel engine is stopped. The diesel engine control device according to any one of claims 1 to 7.
  9. 　前記クランク角制御部は、前記再始動条件成立時における前記コモンレール内の圧力が前記高圧燃料の正常噴射が可能な圧力以上のときには、前記ディーゼルエンジンが圧縮行程から始まるように前記クランク角をずらす制御を行うことを特徴とする請求項７又は８に記載のディーゼルエンジンの制御装置。 The crank angle control unit controls the shift of the crank angle so that the diesel engine starts from the compression stroke when the pressure in the common rail when the restart condition is satisfied is equal to or higher than the pressure at which the high pressure fuel can be normally injected. The control device for a diesel engine according to claim 7 or 8, wherein:
PCT/JP2010/052513 2009-06-15 2010-02-19 Control apparatus for diesel engine WO2010146896A1 (en)

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Cited By (3)

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CN103184944A (en) * 2011-12-29 2013-07-03 罗伯特·博世有限公司 Method for operating petrol engine,
JP2017082695A (en) * 2015-10-29 2017-05-18 株式会社デンソー Start control device of internal combustion engine
JP2018071505A (en) * 2016-11-03 2018-05-10 株式会社デンソー Engine starter and vehicle

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JP2000320367A (en) * 1999-05-12 2000-11-21 Nissan Motor Co Ltd Automatic stop and restart device for engine
JP2006046213A (en) * 2004-08-05 2006-02-16 Toyota Motor Corp Automatic stop/start control method for diesel engine and automatic stop/start control system of diesel engine
JP2008163796A (en) * 2006-12-27 2008-07-17 Mitsubishi Fuso Truck & Bus Corp Control device for internal combustion engine

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JP2000320367A (en) * 1999-05-12 2000-11-21 Nissan Motor Co Ltd Automatic stop and restart device for engine
JP2006046213A (en) * 2004-08-05 2006-02-16 Toyota Motor Corp Automatic stop/start control method for diesel engine and automatic stop/start control system of diesel engine
JP2008163796A (en) * 2006-12-27 2008-07-17 Mitsubishi Fuso Truck & Bus Corp Control device for internal combustion engine

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Publication number Priority date Publication date Assignee Title
CN103184944A (en) * 2011-12-29 2013-07-03 罗伯特·博世有限公司 Method for operating petrol engine,
JP2017082695A (en) * 2015-10-29 2017-05-18 株式会社デンソー Start control device of internal combustion engine
JP2018071505A (en) * 2016-11-03 2018-05-10 株式会社デンソー Engine starter and vehicle
WO2018084111A1 (en) * 2016-11-03 2018-05-11 株式会社デンソー Engine starting device and vehicle

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JP5140191B2 (en) 2013-02-06

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