JP4925409B2 - Control device for high-pressure fuel supply system - Google Patents

Description

  The present invention relates to a high pressure fuel supply device and a component state detection method for an internal combustion engine, and more particularly to a high pressure fuel supply device and a component state detection method provided with a high pressure fuel pump for an internal combustion engine mounted on an automobile or the like.

  Current automobiles are required to reduce exhaust gas substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in automobile exhaust gas from the viewpoint of environmental conservation. In-cylinder injection engines have been developed for the purpose of reducing this.

  An in-cylinder injection engine performs fuel injection by a fuel injection valve directly into a combustion chamber of a cylinder, promotes combustion of injected fuel by reducing the particle size of fuel injected from the fuel injection valve, and emits exhaust gas. It aims to reduce substances and improve engine output.

  In-cylinder injection engines require a high-pressure fuel supply device, and it is important to know the operating state of each component of the high-pressure fuel supply device.

As a prior art, a fuel supply system based on at least one of an input / output signal of a fuel pump control device, a control amount of the fuel pump, an operating state of the fuel pump, an operating state of the internal combustion engine, and a fuel supply state to the fuel injection valve There is one that determines whether or not there is an abnormality (for example, Patent Document 1).
JP 2001-328881 A

  The abnormality detection of the fuel supply system in the prior art detects that there is an abnormality somewhere in the whole fuel system (high pressure pump, fuel injection valve, pressure regulating valve, pressure accumulating chamber), and identifies specific abnormal parts I have n’t gone.

  For this reason, it takes time and effort to specify the failure location when the high-pressure fuel system fails, and control options such as stopping the high-pressure fuel pump are limited for fail-safe control. When the high-pressure fuel pump is stopped, the target fuel pressure for achieving optimal combustion cannot be obtained, resulting in deterioration of combustion stability and exhaust gas performance.

  The present invention has been made in view of such a problem, and an object of the present invention is to detect the state of components of a high-pressure fuel supply device (for example, a fuel injection valve, a pressure regulating valve) and perform optimal control. It is to provide a high-pressure fuel supply device and a component state detection method for an internal combustion engine that contribute to stabilization of combustion and improvement of exhaust gas performance by selecting a method.

  In order to achieve the above object, a high-pressure fuel supply apparatus for an internal combustion engine according to the present invention supplies fuel to a pressure accumulating chamber by a high-pressure fuel pump and directly injects the fuel in the pressure accumulating chamber into a combustion chamber of the internal combustion engine. A high pressure fuel supply system that supplies the valve, a pressure adjustment valve that adjusts the pressure in the pressure accumulation chamber by returning the fuel to a low pressure side when the pressure in the pressure accumulation chamber rises above a predetermined value, A high-pressure fuel supply apparatus for an internal combustion engine comprising a pressure detection means for detecting a fuel pressure and a high-pressure fuel pump control device for controlling the high-pressure fuel pump, wherein the fuel pressure change state is detected based on a change in fuel pressure detected by the pressure detection means. There is a component state detecting means for specifying a component constituting the high pressure fuel supply apparatus and detecting the state of the component.

  In the internal combustion engine high-pressure fuel supply apparatus according to the present invention, preferably, the component is at least one of the fuel injection valve and the pressure regulating valve.

  In the high-pressure fuel supply apparatus for an internal combustion engine according to the present invention, preferably, the component state detecting unit identifies the component based on the amount of change in fuel pressure detected by the pressure detecting unit, and the state of the component Is detected.

  In the internal combustion engine high-pressure fuel supply device according to the present invention, preferably, the component state detection unit identifies the component based on a frequency analysis result of the fuel pressure detected by the pressure detection unit, and Detect state.

  The high-pressure fuel supply apparatus for an internal combustion engine according to the present invention preferably has storage means for storing and holding the state detection result by the component state detection means.

  The high-pressure fuel supply device for an internal combustion engine according to the present invention is preferably configured such that the high-pressure fuel pump control device feedbacks the high-pressure fuel so that the fuel pressure detected by the pressure detecting means becomes a pressure target value of the pressure accumulating chamber. The operation of the pump is controlled, and at least one of the pressure target value of the pressure accumulating chamber and the feedback of the high pressure fuel pump control device is changed according to the state detection result by the component state detecting means.

  The high pressure fuel supply apparatus for an internal combustion engine according to the present invention preferably changes the output per cylinder according to the state detection result by the component state detection means.

  In order to achieve the above object, the component state detection method for a high-pressure fuel supply apparatus for an internal combustion engine according to the present invention pressurizes and supplies the fuel to the pressure accumulation chamber by a high-pressure fuel pump, and the fuel in the pressure accumulation chamber is supplied to the combustion chamber of the internal combustion engine. A high-pressure fuel supply system that supplies fuel to the fuel injection valve that directly injects the fuel, and a pressure adjustment valve that adjusts the pressure in the pressure accumulation chamber by returning the fuel to the low pressure side when the pressure in the pressure accumulation chamber rises above a predetermined value And a pressure detection means for detecting the fuel pressure in the pressure accumulating chamber, and a high pressure fuel pump control device for controlling the high pressure fuel pump. The component constituting the high-pressure fuel supply apparatus is identified from the change in the fuel pressure detected by the means, and the state of the component is detected.

  According to the high pressure fuel supply device for an internal combustion engine according to the present invention, the state of each component of the high pressure fuel supply device (for example, the on / off state of the fuel injection valve, the on / off state of the pressure regulating valve) is detected, and the optimum control method is Since it becomes possible to select, it can contribute to stabilization of combustion and improvement of exhaust gas performance.

  An embodiment of a high-pressure fuel supply device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 shows the overall configuration of a direct injection engine 507 to which a high pressure fuel supply apparatus according to the present invention is applied.

  The in-cylinder injection engine 507 is a multi-cylinder engine, for example, a four-cylinder engine, and a combustion chamber 507c is formed by a piston 507a, a cylinder block 507b, and the like.

  In each combustion chamber 507 c, air passes from an inlet of an air cleaner 502 through an air flow meter (air flow sensor) 503, an electric throttle valve 505 a for controlling the intake flow rate, and a collector 506. Distribution is supplied by an intake pipe 501 connected to the combustion chamber 507c.

  The airflow sensor 503 outputs a signal representing the intake air flow rate to the engine control device (control unit) 515.

  The throttle body 505 is provided with a throttle sensor 504 for detecting the opening degree of the electric throttle valve 505a. The throttle sensor 504 outputs a signal representing the throttle opening to the control unit 515.

Fuel such as gasoline is supplied from the fuel tank 50 and is primarily pressurized by an electric fuel pump (low pressure fuel pump) 51, and is regulated to a constant pressure (for example, 3 kg / cm ² ) by a fuel pressure regulator 52, Furthermore, the secondary pressure is applied to a high pressure (for example, 50 kg / cm ² ) by the cam-driven high-pressure fuel pump 1.

  The secondary pressurized high-pressure fuel is supplied to the common rail 53 and directly injected into the combustion chamber 507c from the fuel injection valve 54 provided for each combustion chamber 507c.

  The fuel injected into the combustion chamber 507c forms an air-fuel mixture with the intake air, and is ignited by the ignition plug 508 by an ignition signal that has been increased in voltage by the ignition coil 522.

  A crank angle sensor (hereinafter referred to as a position sensor) 516 is attached to the crankshaft 507d of the engine 507. The position sensor 516 outputs a signal indicating the rotational position of the crankshaft 507d to the control unit 515. The control unit 515 calculates the engine speed based on the output signal of the position sensor 516.

  Another crank angle sensor (hereinafter referred to as a phase sensor) is attached to the cam shaft 526a of the exhaust valve 526. The phase sensor 511 outputs an angle signal indicating the rotational position of the cam shaft 526a to the control unit 515.

  Since the cam shaft 526a of the exhaust valve 526 is provided with the pump drive cam 100 of the high pressure fuel pump 1, the angle signal indicating the rotation position of the cam shaft 526a indicates the rotation position of the pump drive cam 100 of the high pressure fuel pump 1. An angle signal to be expressed is also input to the control unit 515.

  A water temperature sensor 517 is attached to the cylinder block 507b. The water temperature sensor 517 outputs a water temperature signal indicating the cooling water temperature of the engine 507 to the control unit 515.

  Details of the overall configuration of the high-pressure fuel supply system including the high-pressure fuel pump 1 will be described with reference to FIG.

  The high pressure fuel pump 1 pumps high pressure fuel to the common rail 53. The common rail 53 has a required internal volume and forms a pressure accumulating chamber for high-pressure fuel.

  The common rail 53 is provided with a number of fuel injection valves 54 corresponding to the number of cylinders of the engine 507, and a pressure adjusting valve (hereinafter referred to as a relief valve) 55 and a fuel pressure sensor (pressure detecting means) 56. Yes. The relief valve 55 is a pressure adjustment valve that opens when the fuel pressure in the common rail 53 exceeds a predetermined value and adjusts the pressure by returning the fuel to the low pressure side, and prevents damage to the piping system. Yes.

  The fuel pressure sensor 56 detects the fuel pressure in the common rail 53 and outputs a fuel pressure signal representing the fuel pressure to the control unit 515.

  As shown in FIG. 3, the high-pressure fuel pump 1 includes a cylinder part 7, a pump part 8, and a solenoid part 9. The cylinder portion 7 is disposed below the pump portion 8, and the solenoid portion 9 is disposed on the suction side of the pump portion 8.

  The cylinder part 7 has a plunger 2, a lifter 3, and a plunger lowering spring 4. The plunger 2 reciprocates via the lifter 3 pressed against the pump drive cam 100 that rotates with the rotation of the cam shaft 526a of the exhaust valve 526 in the engine 507, and changes the volume of the pressurizing chamber 12 of the pump unit 8. Let

  The pump unit 8 includes a low-pressure fuel suction passage 10, a pressurization chamber 12, and a high-pressure fuel discharge passage 11, and a suction valve 5 is provided between the suction passage 10 and the pressurization chamber 12.

  The intake valve 5 is a check valve that is urged in the valve closing direction from the pump unit 8 toward the solenoid unit 9 by the spring force of the valve closing spring 5a and restricts the direction of fuel flow. The valve closing spring 5a has a pressure on the pressurizing chamber 12 side equal to or higher than the pressure on the inflow passage 10 side across the suction valve 5 due to the volume change in the pressurizing chamber 12 by the plunger 2. In this case, the suction valve 5 is urged to close.

  A discharge valve 6 is provided between the pressurizing chamber 12 and the discharge passage 11. The discharge valve 6 is energized in the valve closing direction from the pump portion 8 toward the solenoid portion 9 by the spring force of the valve closing spring 6a, and allows only the flow of fuel from the pressurizing chamber 12 toward the discharge passage 11. It is a check valve that restricts the flow direction.

  The solenoid unit 9 includes a solenoid 200 that is an actuator, a suction valve engagement rod 201, and a valve opening spring 202. The suction valve engagement rod 201 is disposed at a position opposite to the suction valve 5, and a tip of the suction valve engagement rod 201 comes into contact with and separates from the suction valve 5, and moves in a direction to close the suction valve 5 by energization of the solenoid 200. . On the other hand, in a state where the energization of the solenoid 200 is released, the suction valve engagement rod 201 is moved in a direction to open the suction valve 5 by the spring force of the valve opening spring 202, and the suction valve 5 is opened. Put it in a state.

  The fuel adjusted to a constant pressure from the fuel tank 50 via the fuel pump 51 and the fuel pressure regulator 52 is guided to the suction passage 10 of the pump unit 8, and then the plunger 2 in the pressurizing chamber 12 in the pump unit 8. The pressure is applied by the reciprocating motion, and the pressure is fed from the discharge passage 11 of the pump unit 8 to the common rail 53.

  As shown in FIG. 4, the control unit 515 is a microcomputer type composed of an MPU 603, an EP-ROM 602, a RAM 604, an I / O LSI 601 including an A / D converter, and the like. Implement a high-pressure fuel pump control device.

  The control unit 515 includes various sensors such as an airflow sensor 503, a throttle sensor 504, a position sensor 516, a phase sensor 511, a water temperature sensor 517, a fuel pressure sensor 56, an accelerator sensor 520 that detects the depression amount of the accelerator pedal 99, and an ignition switch 519. , Taking signals from the switches as inputs, executing predetermined calculation processing, and outputting various control signals calculated as the calculation results to the solenoid 200, the fuel injection valve 54, and the ignition coil 522 of the high-pressure fuel pump 1. Then, the fuel discharge amount control of the high-pressure fuel pump 1, the fuel injection amount control of the fuel injection valve 54, and the ignition timing control are executed.

  The fuel discharge control of the high-pressure fuel pump 1 by the control unit 515 is performed by outputting a drive signal to the solenoid 200 based on each input sensor detection signal (position sensor 516, phase sensor 511, fuel pressure sensor 56).

  FIG. 5 shows an operation timing chart of the high-pressure fuel pump 1. The actual stroke (actual position) of the plunger 2 driven by the pump drive cam 100 is a curve as shown in FIG. 6, but in order to make the positions of the top dead center and the bottom dead center easy to understand, The stroke of the plunger 2 is expressed linearly.

  The plunger 2 moves from the top dead center side to the bottom dead center side according to the urging force of the plunger lowering spring 4 by the rotation of the cam 100, whereby the suction stroke of the pump unit 8 is performed.

  In the intake stroke, the intake valve engaging rod 201 is engaged with the intake valve 5 according to the urging force of the valve opening spring 202 (rod position / open), and the intake valve 5 is moved in the valve opening direction. The pressure in the chamber 12 decreases.

  Next, when the plunger 2 moves from the bottom dead center side to the top dead center side against the biasing force of the plunger lowering spring 4 by the rotation of the cam 100, the compression stroke of the pump unit 8 is performed.

  In the compression stroke, a drive signal (ON signal) of the solenoid 200 is output from the control unit 515 over a predetermined period. When the solenoid 200 is energized (ON state), the suction valve engagement rod 201 moves backward against the urging force of the valve opening spring 202 to disengage from the suction valve 5 (rod position / Closed). As a result, the suction valve 5 moves in the valve closing direction in accordance with the urging force of the valve closing spring 5a, so that the pressure in the pressurizing chamber 12 increases.

  When the suction valve engaging rod 201 is most attracted to the solenoid 200 side and the suction valve 5 synchronized with the reciprocating motion of the plunger 2 is closed to increase the pressure in the pressurizing chamber 12, When the fuel presses the discharge valve 6, the discharge valve 6 opens against the urging force of the valve closing spring 6 a, and high pressure fuel corresponding to the volume reduction of the pressurizing chamber 12 is discharged to the common rail 53 side.

  The drive signal of the solenoid 200 is stopped when the intake valve 5 is closed on the solenoid 200 side (OFF state). However, as described above, the pressure in the pressurizing chamber 12 is high. The intake valve 5 is maintained in a closed state, and fuel is discharged to the common rail 53 side.

  Further, when the plunger 2 moves from the top dead center side to the bottom dead center side according to the biasing force of the plunger lowering spring 4 by the rotation of the cam 100, the suction stroke of the pump unit 8 is performed, and the inside of the pressurizing chamber 12 As the pressure decreases, the intake valve engagement rod 201 is engaged with the intake valve 5 in accordance with the urging force of the valve opening spring 202 and moves in the valve opening direction. The valve is opened in synchronism, and the open state of the valve 5 is maintained. Then, the discharge valve 6 is not opened due to the pressure drop in the pressurizing chamber 12. Thereafter, the above operation is repeated.

  Therefore, when the solenoid 200 is turned on in the middle of the compression process before the plunger 2 reaches the top dead center, the fuel is fed to the common rail 53 from this time, and the fuel is fed once. If it starts, the pressure in the pressurizing chamber 12 rises. Therefore, even if the solenoid 200 is turned off thereafter, the suction valve 5 remains closed, but automatically in synchronism with the start of the suction process. The valve can be opened, and the amount of fuel discharged to the common rail 53 can be adjusted by the output timing of the ON signal of the solenoid 200.

  Further, by calculating an appropriate energization ON timing by the control unit 515 based on the signal from the fuel pressure sensor 56 and controlling the solenoid 200, the pressure of the common rail 53 can be feedback controlled to the target value.

  As a result, the fuel adjusted to a constant pressure from the fuel tank 50 via the fuel pump 51 and the fuel pressure regulator 52 is guided to the suction passage 10 of the pump unit 8 and then into the pressurizing chamber 12 in the pump unit 8. The plunger 2 is pressurized by the reciprocating motion of the plunger 2 and is pumped from the discharge passage 11 of the pump unit 8 to the common rail 53.

  FIG. 7 shows an embodiment of the high-pressure fuel pump control device by the control unit 515.

  The high-pressure fuel pump control apparatus includes a basic angle calculation unit 2001, a target fuel pressure calculation unit 2002, a fuel pressure input processing unit 2003, and a pump control signal calculation unit 2004 which is an embodiment of a unit that calculates a drive signal for the solenoid 200. The pump control signal is output from the pump control signal calculation means 2004 to the solenoid drive means 2009 that controls the energization of the solenoid 200.

  The basic angle calculation means 2001 is configured to output a solenoid ON signal output of the high-pressure fuel pump 1 based on the engine load and the engine speed obtained from the output signals of the airflow sensor 503, throttle sensor 504, position sensor 516, phase sensor 511, and accelerator sensor 520. The basic angle BASA is calculated.

  The target fuel pressure calculating means 2002 calculates the target fuel pressure Ptarget of the high-pressure fuel pump 1 based on the engine load and engine speed obtained from the output signals of the airflow sensor 503, throttle sensor 504, position sensor 516, phase sensor 511, and accelerator sensor 520. calculate.

  As shown in FIG. 8, the pump control signal calculation means 2004 includes a reference angle calculation means 2008 for calculating the timing of the ON signal of the solenoid 200, and a pump for calculating the width of the ON signal, that is, the pump signal energization time. The signal energization time calculation means 2006 has a basic configuration.

  The reference angle calculation means 2008 receives the target fuel pressure Ptarget output from the target fuel pressure calculation means 2002 and the measured fuel pressure Preal output from the fuel pressure sensor 56 output from the fuel pressure input processing means 2003, and the measured fuel pressure Preal relative to the target fuel pressure Ptarget. A deviation calculator 2010 that calculates the deviation of the fuel pressure, and an F / B compensation value calculation unit 2007 that calculates a feedback term (proportional part (P part) / integral part (I part)) of the fuel pressure control from the deviation by the deviation calculator 2010 The reference angle REFANG as a reference for starting the output of the solenoid ON signal is obtained by adding the F / B compensation value (feedback term) from the F / B compensation value calculation unit 2007 to the basic angle BASANG output by the basic angle calculation unit 2001. And an adder 2011 for calculation.

  The pump control signal calculation unit 2004 further includes solenoid operation delay compensation unit 2005. The solenoid operation delay compensation unit 2005 calculates a solenoid operation delay (angle) PUMRE based on the power supply voltage (battery voltage) of the solenoid 200 of the high-pressure fuel pump 1.

  The pump control signal calculation means 2004 calculates the output start angle STANG of the ON signal of the solenoid 200 by adding the operation delay correction amount PUMRE by the solenoid operation delay correction means 2005 to the adder reference angle REFANG by the adder 2012. Is output to the solenoid drive means 2009 as the timing of the ON signal of the solenoid 200.

  The pump signal energization time calculation means 2006 calculates the energization request time TPUMKE of the solenoid 200 of the high-pressure fuel pump 1 based on the operating conditions (battery voltage and engine speed), and outputs this to the solenoid drive means 2009. The value of the energization request time TPUMKE holds the suction valve engagement rod 201 until the suction valve 5 is closed by the pressure of the pump chamber 2 even in the worst condition of solenoid suction force generation where the battery voltage is low and the solenoid resistance is large. Thus, the value is set so that the intake valve 5 can be closed reliably.

  As described above, the command signal related to the output start angle STANG and the energization time TPUMKE is output to the solenoid drive unit 2009, so that the solenoid 200 is driven with the output start angle STANG and the energization time TPUMKE.

  In summary, the high-pressure fuel pump control apparatus of the present embodiment controls the operation of the high-pressure fuel pump 1 in a feedback manner so that the fuel pressure detected by the fuel pressure sensor 56 becomes the target fuel pressure Ptarget (pressure target value of the pressure accumulation chamber). To do.

  As shown in FIG. 9, the high-pressure fuel supply apparatus according to the present embodiment includes a relief valve open / close state determination unit 703 and an injection valve closed adhesion determination unit 704 as component state detection units.

  The relief valve open / close state determination means 703 basically detects the pressure change of the common rail (accumulation chamber) 53 from the output signal (fuel pressure sensor signal) of the fuel pressure sensor 56, and the pressure change amount and the frequency of the pressure (fuel pressure). Based on at least one of the analysis results, the open / close state of the relief valve 55 is determined, and the relief valve open flag #FRELOPEN is turned on / off. The relief valve opening flag #FRELOPEN is stored and held in the relief valve opening / closing state information memory 705 as relief valve opening / closing state information. The relief valve open / close state information memory 705 is allocated to the RAM 604 of the control unit 515.

  FIG. 10A shows the fuel pressure behavior when the relief valve is closed, and FIG. 10B shows the fuel pressure behavior when the relief valve is opened. When the relief valve is opened, it is affected by the valve characteristics, so that the amplitude of the fuel pressure is larger than that when the relief valve is closed, and the vibration mode is also different. The relief valve open / close state determining means 703 performs open / close valve state determination using this fuel pressure characteristic.

  The injection valve closing adhesion determining means 704 basically detects the pressure change of the common rail (accumulation chamber) 53 from the output signal (fuel pressure sensor signal) of the fuel pressure sensor 56, and the pressure change amount and the frequency of the pressure (fuel pressure). From at least one of the analysis results, it is determined whether or not the fuel injection valve 54 is closed, and the injection valve closed fixation flag #FINJCLOSE is turned on / off. The injection valve closing sticking flag #FINJCLOSE is stored and held in the injection valve closing sticking information memory 706 as injection valve closing sticking information. The injection valve closing adhesion information memory 706 is allocated to the RAM 604 of the control unit 515.

  11A shows the fuel pressure behavior when the fuel injection valve 54 is operating normally in a four-cylinder engine, and FIG. 11B shows the fuel pressure behavior when the fuel injection valve 54 is fixedly closed to one cylinder. Yes. The fuel pressure pulsation is generated when the high-pressure fuel pump 1 has a discharge region and a non-discharge region, the fuel pressure increases only in the discharge region, and the fuel is injected into the non-discharge region and the fuel pressure decreases. When the fuel injection valve 54 is closed and fixed, there is no fuel pressure drop, so the behavior of the fuel pressure is different from that in the normal state. The injection valve closed adhesion determination means 704 makes a closed adhesion state determination using this fuel pressure characteristic.

  Next, a specific example 1 of determining the opening / closing state of the relief valve 55 by the relief valve opening / closing state determining means 703 will be described with reference to the flowchart shown in FIG. The open / close valve state determination routine of the relief valve 55 shown in FIG. 12 is executed as an interrupt process by, for example, time synchronization every 10 ms.

  First, the fuel pressure detected by the fuel pressure sensor 56 is read (step 801). Next, the engine speed and the fuel injection amount are read (steps 802 and 803). The purpose of reading the engine speed and the fuel injection amount is to grasp the pulsation cycle of the fuel pressure having characteristics proportional to the engine speed and the pulsation width having characteristics proportional to the fuel injection amount.

  Next, it is determined from the read fuel pressure whether the fuel pressure deviation (difference in fuel pressure upper and lower limit values for a certain period during steady operation) is equal to or greater than a specified value (step 804). If the fuel pressure deviation is greater than or equal to the specified value, it is determined that the relief valve 55 is open, and the relief valve opening flag: # FRELOPEN = 1 (step 806). The prescribed value of the fuel pressure deviation is set by a map of the fuel pressure pulsation width at the engine speed and the fuel injection amount.

  If the fuel pressure deviation is not equal to or greater than a specified value, it is next determined whether the amount of change in fuel pressure (inclination of fuel pressure pulsation) for a certain period in steady operation, that is, the fuel pressure increase rate is equal to or greater than a specified value (step 805). If the fuel pressure increase rate is equal to or greater than the specified value, it is determined that the relief valve 55 is open, and the relief valve open flag: # FRELOPEN = 1 (step 806). The specified value of the fuel pressure increase rate is set by a map of the fuel pressure increase rate at the engine speed and the fuel injection amount.

  If the fuel pressure deviation is not equal to or greater than the specified value and not equal to or greater than the specified value of the fuel pressure increase rate, it is determined that the relief valve 55 is closed, and the relief valve opening flag: # FRELOPEN = 0 (block 807).

  Next, a relief valve opening flag: #FRELOPEN is written (stored) in the relief valve opening / closing state information memory 705 (step 808).

  The flag information FRELOPEN in the relief valve open / close state information memory 705 functions as relief valve open / close state information, and this information makes it possible to quickly identify the failure location at the time of repairing the high pressure fuel system failure.

  Next, specific example 2 of the determination of the open / close state of the relief valve 55 by the relief valve open / close state determination means 703 will be described with reference to the flowchart shown in FIG. The open / close valve state determination routine of the relief valve 55 shown in FIG. 13 is also executed as an interrupt process by, for example, time synchronization every 10 ms.

  First, the fuel pressure detected by the fuel pressure sensor 56 is read (step 901). Next, the engine speed is read (step 902). The purpose of reading the engine speed is to grasp the pulsation cycle of the fuel pressure having characteristics proportional to the engine speed.

  Next, frequency analysis of the read fuel pressure is performed (step 903). In this frequency analysis, in order to reduce the calculation load of the control unit 515, fast Fourier transform, which is characterized by a small amount of calculation, is performed.

  Next, the frequency analysis result (spectrum) of the fuel pressure is compared with the frequency analysis value (spectrum) stored in advance when the relief valve is opened (step 904). When the frequency analysis result of the fuel pressure and the frequency analysis value stored in advance when the relief valve is opened are the same, it is determined that the relief valve 55 is open, and the relief valve opening flag: # FRELOPEN = 1 (step 905).

  In contrast, if the frequency analysis result of the fuel pressure is different from the frequency analysis value stored in advance when the relief valve is opened, it is determined that the relief valve 55 is closed, and the relief valve opening flag: # FRELOPEN = 0 (block 906).

  Next, a relief valve opening flag: #FRELOPEN is written (stored) in the relief valve open / close state information memory 705 (step 907).

  Also in this case, the flag information FRELOPEN in the relief valve open / close state information memory 705 functions as the relief valve open / close state information, and this information makes it possible to quickly identify the failure location at the time of repairing the high pressure fuel system failure.

  Further, based on the flag information in the relief valve open / close state information memory 705, the change of the target fuel pressure Ptarget output by the target fuel pressure calculating means 2002, and the feedback term (proportional part (P part) of the F / B compensation value calculating part 2007 are shown. -Either one of the changes in the integral (I) is changed at least to optimize the fuel pressure control.

  Next, the process for optimizing the fuel pressure control will be described with reference to the flowchart shown in FIG. This optimization processing routine is executed as an interrupt routine every predetermined time.

  First, the relief valve open flag: #FRELOPEN written in the relief valve open / close state information memory 705 is read (step 1001).

  Next, it is determined whether or not the relief valve opening flag: # FRELOPEN = 1 (step 1002).

  If # FRELOPEN = 1, it is determined whether the relief valve 55 is open, and the control is switched to the high-pressure fuel pump control for opening the relief valve (step 1003).

  In contrast, if # FRELOPEN = 1, it is determined that the relief valve 55 is closed, and normal pump control is continued (step 1004).

  In the high-pressure fuel pump control for opening the relief valve, first, as shown in FIG. 15, the target fuel pressure Ptarget output by the target fuel pressure calculating means 2002 is changed (step 1101). Next, the feedback term (proportional part (P part) / integral part (I part)) of the fuel pressure control by the F / B compensation value calculation unit 2007 is changed (step 1102).

  When the relief valve is open, the target fuel pressure Ptarget is lowered from that during normal pump control, the relief valve is reclosed to suppress pulsation, and the target fuel pressure Ptarget is set within the controllable range to prevent feedback term divergence. can do. Further, by reducing the gain of the feedback term, the promotion of pulsation can be prevented.

  The relief valve open / close state determination means 703 may determine the open / close valve state of the relief valve 55 by a combination of the above-described specific example 1 and specific example 2, OR logic or AND logic.

  Next, a specific example of the determination of the closed adhesion of the fuel injection valve 54 by the injection valve closed adhesion determination means 704 will be described with reference to the flowchart shown in FIG. The routine for determining whether the fuel injection valve 54 is firmly closed shown in FIG. 16 is executed as an interrupt process by, for example, time synchronization every 10 ms.

First, the fuel pressure detected by the fuel pressure sensor 56 is read (step 1201).
Next, it is determined whether or not the read fuel pressure is a fuel pressure behavior when the fuel injection valve 54 is closed and fixed (step 1202).

  Next, the determined closed adhesion determination information (injection valve closed adhesion flag: #FINJCLOSE) is stored in the injection valve closed adhesion information memory 706 (step 1203).

  The flag information FINJCLOSE in the injection valve closing sticking information memory 706 functions as injection valve closing sticking state information, and this information makes it possible to quickly identify the fault location at the time of repairing the high pressure fuel system fault.

  Next, details of the determination of the injection valve closed sticking in step 1202 will be described with reference to the flowchart shown in FIG.

  First, the engine speed is read (step 1301). The purpose of reading the engine speed is to grasp the pulsation cycle of the fuel pressure having characteristics proportional to the engine speed.

  Next, frequency analysis of the read fuel pressure is performed (step 1302). In this frequency analysis, in order to reduce the calculation load of the control unit 515, fast Fourier transform, which is characterized by a small amount of calculation, is performed.

  Next, the fuel pressure frequency analysis result (spectrum) is compared with the frequency analysis value (spectrum) stored in advance when the injector is closed (step 1303). If the frequency analysis result of the fuel pressure is the same as the frequency analysis value stored in advance when the injection valve is closed, it is determined that the fuel injection valve 54 is closed and fixed, and the injection valve closed and fixed flag: # FINJCLOSE = 1 (step 1304).

  On the other hand, if the frequency analysis result of the fuel pressure is different from the frequency analysis value stored in advance when the injection valve is closed, it is determined that the fuel injection valve 54 is not closed and the injection valve is closed. Flag: # FINJCLOSE = 0 (step 1305).

  FIG. 18 shows the details of the injection valve closing sticking determination routine in step 1202 in the four-cylinder engine.

  Also in this determination routine, first, the engine speed is read (step 1301). The purpose of reading the engine speed is to grasp the pulsation cycle of the fuel pressure having characteristics proportional to the engine speed.

  Next, frequency analysis of the read fuel pressure is performed (step 1302). In this frequency analysis, in order to reduce the calculation load of the control unit 515, fast Fourier transform, which is characterized by a small amount of calculation, is performed.

Next, the frequency analysis result (spectrum) of the fuel pressure is compared with the frequency analysis value (spectrum) stored in advance for each cylinder when the injector is closed (steps 1303 to 1306).
If the frequency analysis result of the fuel pressure and the frequency analysis value stored in advance for the corresponding cylinder when the injection valve is closed are the same, it is determined that the fuel injection valve 54 for that cylinder is closed and fixed. The cylinder number is written in the injection valve closed sticking RAM: INJCLOSE in the injection valve closed sticking information memory 706 (steps 1307 to 1310). For example, if it is determined that the # 3 cylinder fuel injection valve 54 is closed and stuck, INJCLOSE = H'03 is written.

  If it is determined that the fuel injection valve 54 of any cylinder is not closed and fixed, INJCLOSE = H'00 is written (step 1311).

  By the injection valve closing sticking information INJCLOSE in the injection valve closing sticking information memory 706, it becomes possible to quickly identify the fault location at the time of repairing the high pressure fuel system fault.

  Based on the flag information FINJCLOSE in the relief valve open / close state information memory 705 and the injection valve closed sticking information INJCLOSE, the output per cylinder is changed to optimize the fuel injection.

  Next, the fuel injection optimizing process will be described with reference to the flowchart shown in FIG. This optimization processing routine is executed as an interrupt routine every predetermined time.

  First, the injection valve closed fixation flag: #FINJCLOSE written in the injection valve closed fixation information memory 706 is read (step 1401).

  Next, it is determined whether or not the injection valve closed sticking flag: # FINJCLOSE = 1 (step 1402).

  If # FINJCLOSE = 1, it is determined that the fuel injection valve 54 is closed and fixed, and the control is switched to the control for closing the fuel injection valve (step 1403).

  On the other hand, if # FINJCLOSE = 1, it is determined that the fuel injection valve 54 is not closed and fixed, and normal control is continued (step 1404).

  As shown in FIG. 20, in the fuel injection valve closing adhering control, first, the target fuel pressure Ptarget output by the target fuel pressure calculating means 2002 is changed (step 1501). Next, the feedback term (proportional part (P part) / integral part (I part)) of the fuel pressure control by the F / B compensation value calculation unit 2007 is changed (step 1502).

  When the fuel injection valve is closed, the target fuel pressure Ptarget can be increased from that during normal control to secure the injection flow rate, and the feedforward component can be corrected to an appropriate value to prevent feedback term divergence. Further, by reducing the feedback gain, the promotion of pulsation can be prevented.

  Further, the valve opening time, throttle opening, and ignition timing of the fuel injection valve 54 are changed (steps 1503 to 1505). Thereby, after the fuel injection valve 54 is closed and fixed, the output before the injection valve is fixed can be maintained by the fuel injection valve 54 that is not closed and fixed.

The present embodiment has the following functions by the above-described configuration.
In this embodiment, it is possible to identify and detect the state of the components of the high-pressure fuel supply system such as the fuel injection valve 54 and the relief valve 55, and to select an optimal control method according to the detection result. Even when the fuel supply system is abnormal, it is possible to stabilize combustion and improve exhaust gas performance.

  FIG. 21 is a time chart showing the effect of the high-pressure fuel supply apparatus according to the present invention. In this embodiment, when the relief valve is abnormally opened, the control is changed to the relief valve opening control without prohibiting the high pressure fuel pump control, so that the fuel pressure in the common rail 53 can be secured. By securing the fuel pressure, misfire can be prevented and the combustion state can be stabilized, thereby contributing to the reduction of exhaust gas.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various changes in design can be made without departing from the spirit of the present invention described in the claims. It is possible to do.

The block diagram which shows the whole structure of the cylinder injection engine to which the high pressure fuel supply apparatus by this invention is applied. The block diagram which shows one Embodiment of the high pressure fuel supply apparatus of the internal combustion engine by this invention. The block diagram of the high-pressure fuel pump used for the high-pressure fuel supply apparatus of the internal combustion engine by this invention. 1 is a block diagram of a control unit of a direct injection engine to which a high pressure fuel supply device according to the present invention is applied. The timing chart which shows the operation | movement timing of the high pressure fuel pump used for the high pressure fuel supply apparatus of the internal combustion engine by this invention. Supplementary explanatory drawing of an operation timing chart. 1 is a block diagram showing an embodiment of a high-pressure fuel pump control device included in a high-pressure fuel supply device for an internal combustion engine according to the present invention. The block diagram which shows the detail of the pump control signal calculation means of the high pressure fuel pump control apparatus of this embodiment. The block diagram which shows one Embodiment of the component-part state detection means which the high-pressure fuel supply apparatus of the internal combustion engine by this invention contains. (A) is a graph showing the fuel pressure behavior in the common rail when the relief valve is closed, and (b) is a graph showing the fuel pressure behavior in the common rail when the relief valve is open. (A) is a graph showing the fuel pressure behavior when the fuel injection valve is normal, and (b) is a graph showing the fuel pressure behavior within the common rail when the fuel injection valve is closed. The flowchart which shows the specific example 1 of the relief valve opening / closing valve state determination by the relief valve opening / closing state determination means of this embodiment. The flowchart which shows the specific example 2 of the relief valve opening / closing valve state determination by the relief valve opening / closing state determination means of this embodiment. 6 is a flowchart showing a fuel pressure control optimization processing routine according to the present embodiment. The flowchart of the relief valve closing pump control in the optimization processing routine of the fuel pressure control of this embodiment. The flowchart which shows the specific example of the closed sticking determination of the fuel injection valve by the injection valve closed sticking judgment means of this embodiment. The flowchart of the fuel-injection-valve closing adhesion determination routine by the injection-valve closing adhesion determination means of this embodiment. The flowchart of the injection valve closed sticking determination routine in a 4-cylinder engine. The flowchart which shows the optimization process routine of the fuel injection of this embodiment. The flowchart of the control at the time of injection valve closed adhering in the optimization process routine of the fuel injection of this embodiment. The time chart which shows the effect of the high-pressure fuel supply apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High pressure fuel pump 53 Common rail 54 Fuel injection valve 55 Relief valve 56 Fuel pressure sensor 507 In-cylinder injection engine 515 Control unit 703 Relief valve open / close state determination means 704 Injection valve close / stick state determination means 705 Relief valve open / close state information memory 706 Information memory

Claims (4)

A high-pressure fuel pump is used to pressurize and supply fuel to the accumulator, and the high-pressure fuel supply system supplies the fuel in the accumulator to a fuel injection valve that directly injects the fuel into the combustion chamber of the internal combustion engine. A control device for a high-pressure fuel supply apparatus, comprising: a pressure adjusting valve in which a valve opening pressure is set so as to prevent damage to the fuel supply system; and a pressure detection means for detecting a fuel pressure in the pressure accumulating chamber,
The control device determines an open / close state of the pressure regulating valve based on a spectrum obtained by a fuel pressure change amount and a fuel pressure amplitude or a fuel pressure frequency analysis detected by the pressure detection means. A control device for a high-pressure fuel supply apparatus, comprising: means. 2. The control device for a high-pressure fuel supply apparatus according to claim 1 , further comprising storage means for storing and holding the detection result of the open / closed state. The high-pressure fuel pump control device controls the operation of the high-pressure fuel pump in a feedback manner so that the fuel pressure detected by the pressure detection means becomes a pressure target value of the pressure accumulation chamber, and detects the open / close state. 3. The control device for a high pressure fuel supply apparatus according to claim 1, wherein at least one of a pressure target value of the pressure accumulating chamber and a feedback amount of the high pressure fuel pump control device is changed according to a result. The control device for a high-pressure fuel supply apparatus according to any one of claims 1 to 3 , wherein an output per cylinder is changed in accordance with a detection result of the open / close state.

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