JP5140191B2 - Diesel engine control device - Google Patents

Description

  The present invention relates to a diesel engine control device, and more particularly to a diesel engine control device used for controlling a diesel engine capable of idling stop control.

  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.

  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.

  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).

JP 2008-163796 A (the whole sentence, all figures)

  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.

  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 about 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. .

  The fuel injection valve used in the accumulator fuel injection apparatus includes 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.

  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.

  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.

  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 when 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.

  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.

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 that allows normal pressure injection of high-pressure fuel when the diesel engine restarts while the diesel engine is stopped Diesel engine to reach more quickly Comprising a crank angle control unit for controlling shifting of the crank angle, the crank angle control unit, the pressure in the common rail to the maximum number of times of delivering high-pressure pump required to be at least capable of normal injection pressure of the high pressure fuel in response, the control device for a diesel engine, characterized that you determine the target position to shift the crank angle is provided, it is possible to solve the problems described above.

In another aspect of the present invention, a high-pressure pump that is driven when the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and fuel that is connected to the common rail and flows into the cylinder of the diesel engine. In a diesel engine control device for controlling a diesel engine having an accumulator fuel injection device having a plurality of fuel injection valves for injecting into the diesel engine, the diesel engine is stopped when a predetermined idling stop condition is satisfied In addition, an idling stop control unit that performs control for restarting the diesel engine when a predetermined restart condition is satisfied, and when the diesel engine is stopped, the pressure in the common rail is normally injected when the diesel engine is restarted. Diese to reach more quickly than possible pressure Comprising a crank angle control unit for controlling shifting of the crank angle of the engine, the crank angle control unit in accordance with the lift position of the plunger of the high-pressure pump of the fuel injection timing at the time of restart, the target position to shift the crank angle This is a control device for a diesel engine.

In another aspect of the present invention, a high-pressure pump that is driven when the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and fuel that is connected to the common rail and flows into the cylinder of the diesel engine. In a diesel engine control device for controlling a diesel engine having an accumulator fuel injection device having a plurality of fuel injection valves for injecting into the diesel engine, the diesel engine is stopped when a predetermined idling stop condition is satisfied In addition, an idling stop control unit that performs control for restarting the diesel engine when a predetermined restart condition is satisfied, and when the diesel engine is stopped, the pressure in the common rail is normally injected when the diesel engine is restarted. Diese to reach more quickly than possible pressure Comprising a crank angle control unit for controlling shifting of the crank angle of the engine, the crank angle control unit, the pressure in the common rail when the diesel engine is restarted to quickly reach the above capable normal injection pressure of the high pressure fuel thereby calculating respective target positions of the crank angle for each of a plurality of fuel injection valves, of the plurality of target position calculated respectively, and wherein the shifting the crank angle at the target position shift amount of the crank angle is minimized It is a control device for a diesel engine.

In another aspect of the present invention, a high-pressure pump that is driven when the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and fuel that is connected to the common rail and flows into the cylinder of the diesel engine. In a diesel engine control device for controlling a diesel engine having an accumulator fuel injection device having a plurality of fuel injection valves for injecting into the diesel engine, the diesel engine is stopped when a predetermined idling stop condition is satisfied In addition, an idling stop control unit that performs control for restarting the diesel engine when a predetermined restart condition is satisfied, and when the diesel engine is stopped, the pressure in the common rail is normally injected when the diesel engine is restarted. Diese to reach more quickly than possible pressure When provided with a crank angle control unit for controlling shifting of the crank angle of the engine, and a pump low pressure pump supplying fuel to the high-pressure pump is driven independently of the rotation state of the diesel engine, a crank angle The control unit is a control device for a diesel engine that selectively performs control for advancing or retreating the crank angle with a state where the high-pressure pump is in a fuel pressure feed stroke as a target position .

In another aspect of the present invention, a high-pressure pump that is driven when the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and fuel that is connected to the common rail and flows into the cylinder of the diesel engine. In a diesel engine control device for controlling a diesel engine having an accumulator fuel injection device having a plurality of fuel injection valves for injecting into the diesel engine, the diesel engine is stopped when a predetermined idling stop condition is satisfied In addition, an idling stop control unit that performs control for restarting the diesel engine when a predetermined restart condition is satisfied, and when the diesel engine is stopped, the pressure in the common rail is normally injected when the diesel engine is restarted. Diese to reach more quickly than possible pressure Comprising a crank angle control unit for controlling shifting of the crank angle of the engine, and when the low-pressure pump supplying fuel to the high-pressure pump is a pump driven in dependence on the rotational state of the diesel engine, a crank angle control The control unit of the diesel engine is characterized in that the crank angle is advanced or retracted with a target position in a state where the high pressure pump is in a fuel intake stroke so as to ensure the maximum number of pumping times of the high pressure pump. is there.

In another aspect of the present invention, a high-pressure pump that is driven when the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and fuel that is connected to the common rail and flows into the cylinder of the diesel engine. In a diesel engine control device for controlling a diesel engine having an accumulator fuel injection device having a plurality of fuel injection valves for injecting into the diesel engine, the diesel engine is stopped when a predetermined idling stop condition is satisfied In addition, an idling stop control unit that performs control for restarting the diesel engine when a predetermined restart condition is satisfied, and when the diesel engine is stopped, the pressure in the common rail is normally injected when the diesel engine is restarted. Diese to reach more quickly than possible pressure A crank angle control unit for controlling shifting of the crank angle of the engine, includes a rail pressure detector for detecting pressure in the common rail, the crank angle control unit has a pressure in the common rail detected during establishment restart condition, high pressure A control apparatus for a diesel engine, wherein a target position for shifting a crank angle is determined based on a difference from a pressure at which normal fuel injection is possible .

In another aspect of the present invention, a high-pressure pump that is driven when the diesel engine is driven, a common rail that accumulates fuel pressurized by the high-pressure pump, and fuel that is connected to the common rail and flows into the cylinder of the diesel engine. In a diesel engine control device for controlling a diesel engine having an accumulator fuel injection device having a plurality of fuel injection valves for injecting into the diesel engine, the diesel engine is stopped when a predetermined idling stop condition is satisfied In addition, an idling stop control unit that performs control for restarting the diesel engine when a predetermined restart condition is satisfied, and when the diesel engine is stopped, the pressure in the common rail is normally injected when the diesel engine is restarted. Diese to reach more quickly than possible pressure Comprising a crank angle control unit for controlling shifting of the crank angle of the engine, a rail pressure detector for detecting pressure in the common rail, the crank angle control unit, the normal pressure in the common rail high-pressure fuel during the stop of the diesel engine A control device for a diesel engine that performs control to shift a crank angle when pressure becomes less than a pressure at which injection is possible .

  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.

  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.

  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 “the 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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

It is a figure which shows the structural example of the pressure accumulation type fuel-injection apparatus of a diesel engine. It is a figure which shows the structural example of the control apparatus of the diesel engine concerning the 1st Embodiment of this invention. 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. 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. 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. 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. It is a figure for demonstrating 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.

  DESCRIPTION OF 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.

[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.

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.

  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.

  The electric low pressure pump 2 and the pressurizing chamber 5 a of the high pressure pump 5 are 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 30 a to 30 c 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. 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. .

  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.

  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.

  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 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.

  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. 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. 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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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. 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.

  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) Control when the rail pressure becomes less than the injectable pressure (control mode 1)
3 to 6 are diagrams for explaining a crank angle adjustment method that is 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. Further, each drawing is 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.

  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.

  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.

  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.

  For example, it is assumed that the diesel engine 40 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 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 °.

  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.

  Further, it is assumed that the diesel engine 40 is stopped at the 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 °.

  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.

  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 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 −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 °.

  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.

  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.

  In addition, as in the example of FIG. 4, if it is desired to start fuel injection at the 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.

  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.

  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.

  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.

  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.

  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) 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.

  Specifically, in the diesel engine 40, an intake stroke, a compression stroke, an explosion stroke, and an 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.

  FIG. 7 shows the relationship between the lift position of the piston in one cylinder and the crank angle Ca of the diesel engine 40. 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). 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.

  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.

  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.

  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. The process proceeds to step S14 where the crank angle shift control in the control mode 2 is performed.

  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.

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.

  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 are performed. 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.

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.

  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.

[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.

  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.

  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).

  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.

  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 has been described in the first embodiment. It is a figure equivalent to FIG. 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 atmospheric pressure to the injectable pressure Pr0 or more. It is an example of an apparatus. In FIG. 9, 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.

  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.

  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.

  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 °.

  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 °.

  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.

  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.

  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.

  According to the diesel engine control method of the present embodiment described above, when the rail pressure becomes less than the injectable pressure while the diesel engine is stopped by the idling stop control, the engine restart condition is satisfied, and the diesel engine 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 (8)

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;
Equipped with a,
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. A diesel engine control device. 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;
With
The crank angle control unit in accordance with the lift position of the plunger of the high pressure pump of the fuel injection timing at the time of restart, the controller features and to Lud I over diesel engines to determine the target position to shift the crank angle. 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;
With
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. with each operation, among the plurality of the target position calculated respectively, the controller features and to Lud I over diesel engine by shifting the crank angle to the target position shift amount of the crank angle is minimized. 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;
With
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. controller features and to Lud I over diesel engine that performs control to advance or retreat angle of the crank angle as a position. 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;
With
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 high-pressure pump control device features and to Lud I over diesel engines that the state performs control to advance or retreat angle of the crank angle as the target position in the fuel intake stroke. 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;
Comprising a rail pressure detector for detecting the pressure of the previous SL 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. controller features and to Lud I over diesel engines. 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;
Comprising a rail pressure detector for detecting the pressure of the previous SL 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 control device of Lud I over diesel engine. 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 6 or 7 , wherein:

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