JP4857371B2 - High pressure fuel pump control device for engine - Google Patents

Description

  The present invention relates to a high-pressure fuel pump control device for an engine, and more particularly to a high-pressure fuel pump control device capable of variably adjusting a discharge amount of high-pressure fuel pumped to a fuel injection valve.

  Current automobiles reduce specific substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in automobile exhaust gas from the viewpoint of environmental conservation, that is, improve exhaust emission characteristics. In order to satisfy these requirements, development of a direct injection engine (in-cylinder injection engine) has been performed. Such an in-cylinder injection engine performs fuel injection by a fuel injection valve directly into a combustion chamber of a cylinder, promotes combustion of the injected fuel by reducing the particle size of fuel injected from the fuel injection valve, It aims to improve exhaust emission characteristics and engine output.

  Here, in order to reduce the particle size of the fuel injected from the fuel injection valve, means for increasing the pressure of the fuel is required. For this reason, a high-pressure fuel pump that pumps high-pressure fuel to the fuel injection valve is used. Has been.

  As one form of a high-pressure fuel pump, a pressurizing chamber, a plunger that pressurizes fuel in the pressurizing chamber, a fuel passage valve (suction valve) provided in the pressurizing chamber, and an actuator that operates the passage valve And by closing the passage valve in the discharge stroke (plunger ascent stroke), the fuel is pumped to the fuel pressure accumulation chamber (common rail).

  In the control for this pump, the timing for closing the passage valve is set according to the fuel pressure, and the angle or time control is performed at the set timing based on the REF signal generated from the cam angle signal and the crank angle signal. By outputting a solenoid drive signal (pulse) which is an actuator drive signal, the passage valve is closed.

  However, immediately after the start of engine start (start of cranking), the phases of the cam angle and the crank angle are not fixed, and the REF signal is not generated. For this reason, it is impossible to set the timing for closing the passage valve. Accordingly, various high-pressure fuel pump control techniques have been proposed immediately after the start of the engine, that is, within the period from the start of the engine to the determination of the crank angle and cam angle phases.

  For example, Patent Document 1 below outputs the actuator drive signal at a predetermined crank angle phase within a period from when the crank angle signal is recognized until the phase of the crank angle and the cam angle is determined, that is, from the start of the start. It has been proposed to output the actuator drive signal (pulse) at least twice within a period until it can be performed.

  Further, in Patent Document 2 below, when starting an in-cylinder injection engine having a high-pressure fuel pump drivingly connected to a crankshaft, before the timing at which the phase of the crank angle is determined, the spill valve of the high-pressure fuel pump is described. After energization is performed in a cycle that consists of a very short period of time and the phase of the crank angle is determined, the fuel pressure control by such duty control is stopped, and the spill valve closing start timing is set every predetermined timing. The fuel is boosted by setting and closing the spill valve at the set valve closing start timing. The timing for switching between the former and the latter fuel pressure control is set to a period from immediately after the start of the discharge stroke of the high-pressure fuel pump to a predetermined valve closing start timing calculation timing.

JP 2001-182597 A (pages 1 to 24, FIGS. 1 to 22) Japanese Patent Laying-Open No. 2003-41982 (pages 1 to 13 and FIGS. 1 to 9)

  In the high-pressure fuel pump control apparatus described in Patent Document 1, an actuator drive signal (pulse) is substantially (several times) during the period from the start of start until the phase of the crank angle and the cam angle is determined. Since the power is output, the energization time to the actuator of the high-pressure fuel pump is increased, the current consumption is increased, and there is a possibility that the solenoid constituting the actuator is likely to be thermally damaged and the durability thereof is lowered. There is a fear.

  Further, the technique described in Patent Document 2 aims at avoiding pressure drop of the high-pressure fuel pump at the time of engine start, and uses a crank angle signal for setting the switching timing. When the high pressure fuel pump is drivingly connected to the camshaft, in order to increase the pressure reliably, the duty control is performed in a cycle consisting of a very short time as described above, taking into account the maximum mounting variation between the crankshaft and the pump drive cam. If there is little variation, an extra signal is output and current consumption increases.

  Furthermore, since each of the conventional techniques cannot be controlled by the set valve closing start timing before the crank angle phase is determined, the control by the drive signal setting means other than the timing control is performed. Although described, no special consideration is given to the determination of whether or not to perform the control before determining the phase of the crank angle. In addition, since each of the conventional techniques performs a duty control, there is a period in which a valve opening signal (drive output OFF) is output in the pump discharge stroke, and thus there is a possibility that the pump intake valve cannot be closed reliably, that is, There is a possibility that the pressure does not increase.

  The present invention has been made in view of such problems, and the object of the present invention is that the pressure of the fuel supplied to the fuel injection valve can be reliably controlled to the target fuel pressure and is good. To provide a high-pressure fuel pump control device for an engine that can improve combustion, improve exhaust emission characteristics and fuel consumption, and improve durability of the high-pressure fuel pump and reduce current consumption is there.

  In order to achieve the above object, a high-pressure fuel pump control device according to the present invention basically includes a fuel injection valve for directly injecting fuel in a fuel accumulator chamber into a combustion chamber, a pressurizing chamber, and the pressurizing chamber. An engine having a plunger for pressurizing the fuel, a fuel passage valve provided in the pressurization chamber, and a high-pressure fuel pump having an actuator for operating the passage valve and pumping the fuel into the fuel pressure accumulation chamber In order to make the discharge amount of the high-pressure fuel pump variable, the actuator has a control means for controlling the output of the actuator drive signal. Within a period until it becomes possible to output at the crank angle phase, the output of the actuator drive signal is started and the output of the actuator drive signal is stopped. The grayed, are to be set based on the fuel pressure in the accumulation chamber.

  In a preferred aspect, the control means outputs the actuator drive signal when the fuel pressure in the pressure accumulating chamber is increased by a predetermined value or more per unit time, or when the pressure difference from the start time becomes a predetermined value or more. To be stopped.

  Preferably, the control means stops the output of the actuator drive signal when the crank angle signal is recognized a predetermined number of times or more.

  Preferably, the control means sets the predetermined number of times based on a battery voltage.

  Preferably, the control means stops the output when a predetermined period elapses after the output of the actuator drive signal is started.

  Preferably, the control means sets the timing for stopping the output of the actuator drive signal based on a crank angle signal or a cam angle signal indicating a discharge range of the high-pressure fuel pump.

  In another preferred aspect of the high-pressure fuel pump control device according to the present invention, the control means starts the start within a period from the start of the start until the actuator drive signal can be output at a predetermined crank angle phase. When the crank angle signal from is recognized a predetermined number of times or more, output of the actuator drive signal is started.

  Preferably, the control means starts outputting the actuator driving signal when the fuel pressure in the pressure accumulating chamber is not more than a predetermined value.

  Preferably, the control means starts outputting the actuator drive signal when the engine coolant temperature is below a predetermined value.

  Preferably, the control means starts outputting the actuator drive signal when a predetermined period has elapsed since the previous output stop of the actuator drive signal.

  Preferably, the control means sets the predetermined period based on a previous output time of the actuator drive signal and / or a crank angle request value.

  Preferably, the control means sets the timing for starting the output of the actuator drive signal based on a crank angle signal or a cam angle signal indicating a discharge range of the high-pressure fuel pump.

  In another preferable aspect of the high pressure fuel pump control device according to the present invention, the control means includes the actuator within a period from the start of the start until the actuator drive signal can be output at a predetermined crank angle phase. The drive signal is continuously output for a predetermined period.

  The high-pressure fuel pump control device for an engine according to the present invention starts output of the solenoid drive signal and accumulates pressure during a period from the start of start until the solenoid drive signal can be output at a predetermined crank angle phase. When the fuel pressure in the room is increased by a predetermined value or more per unit time, or when the pressure difference from the start time becomes a predetermined value or more, the output of the solenoid drive signal is stopped. Can be reliably boosted to the required pressure, the robustness to good combustion is improved, and the total energization time of the solenoid at start-up can be shortened compared to the conventional example, so a high-pressure fuel pump It is possible to improve durability and reduce current consumption.

  Further, since the output start timing of the solenoid drive signal is delayed from the start of the start, the total energization time of the solenoid can be shortened, and the durability of the high-pressure fuel pump 60 can be further improved and the current consumption can be reduced. Can be planned.

1 is an overall configuration diagram showing an embodiment of a high-pressure fuel pump control device according to an embodiment together with an engine to which it is applied. The block diagram with which it uses for description of the control unit which comprises the principal part of the high-pressure fuel pump control apparatus shown by FIG. FIG. 1 shows an overall configuration of a fuel supply system including a high-pressure fuel pump. FIG. 2 is an enlarged longitudinal sectional view of the high pressure fuel pump shown in FIG. 1. The time chart used for operation | movement description of a high pressure fuel pump. Supplementary explanatory drawing of the time chart of FIG. The functional block diagram of the high pressure fuel pump control which a control unit performs. The functional block diagram which shows the more detailed structure of the pump control signal calculation means shown by FIG. Time chart of high-pressure fuel pump control by the control unit. The time chart used for description of the output control of the solenoid drive signal by a control unit. The figure which shows the discharge flow volume characteristic of a high pressure fuel pump. The functional block diagram of the high-pressure fuel pump control at the time of starting which a control unit performs. The flowchart of an example of the high pressure fuel pump control at the time of starting which a control unit performs. 14 is a flowchart showing details of drive signal output start flag determination processing in step 1303 of FIG. 13. 14 is a flowchart showing details of drive signal output end flag determination processing executed in step 1304 of FIG. 13. FIG. 15 is a functional block diagram showing processing up to a determination as to whether or not a predetermined period has elapsed in step 1405 of FIG. FIG. 17 is a time chart for explaining the crank angle request value of FIG. 16. The time chart with which it uses for description of operation | movement and an effect of one Embodiment of the high pressure fuel pump control apparatus which concerns on this invention. The time chart with which it uses for description of operation | movement and an effect of other embodiment of the high pressure fuel pump control apparatus which concerns on this invention.

  Embodiments of a high-pressure fuel pump control device for an engine according to the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall configuration diagram of an engine showing an embodiment of the present invention together with an example of an in-cylinder in-cylinder injection engine to which the embodiment is applied.

  The illustrated in-cylinder injection engine 10 is, for example, an in-line four-cylinder engine having four cylinders # 1, # 2, # 3, and # 4, and includes a cylinder head 11, a cylinder block 12, and a cylinder block 12. And a piston 15 that is slidably inserted into the piston 15. A combustion chamber 17 is defined above the piston 15. In the combustion chamber 17, an ignition plug 35 to which a high voltage is applied from the ignition coil 34 and a fuel injection valve 30 that injects fuel directly into the combustion chamber 17 are provided. In the drawing, the ignition plug 35 and the fuel injection valve 30 are provided side by side on the left and right of the ceiling portion of the combustion chamber 17 for convenience, but their arrangement positions can be set as appropriate.

  Air to be used for fuel combustion is taken from an inlet 21a of an air cleaner 21 provided at the start end of the intake passage 20, passes through an air flow sensor 24, passes through a throttle body 26 in which an electric throttle valve 25 is accommodated. The cylinder 27 enters the cylinder 27 via a branch passage portion that forms a downstream portion of the intake passage 20 from the collector 27 and an intake valve 28 that is disposed at the downstream end of the collector passage and that is driven to open and close by an intake camshaft 29. Sucked into the combustion chambers 17 of # 1, # 2, # 3, and # 4.

  The air-fuel mixture of the air sucked into the combustion chamber 17 and the fuel injected from the fuel injection valve 30 is ignited by the spark plug 35 and explosively burned. The combustion waste gas (exhaust gas) is exhausted by the exhaust camshaft 49. The exhaust gas is discharged to the exhaust passage 40 through the exhaust valve 48 that is driven to open and close, and after being purified by the catalytic converter 46 disposed in the exhaust passage 40, the exhaust gas is discharged to the outside.

On the other hand, fuel such as gasoline injected from the fuel injection valve 30 is primarily pressurized from the fuel tank 50 by the low-pressure fuel pump 51 and regulated to a constant pressure (for example, 3 kg / cm ² ) by the fuel pressure regulator 52. At the same time, in the high pressure fuel pump 60 driven by the pump drive cam 47 provided on the exhaust camshaft 49, the secondary pressure is increased to a higher pressure (for example, 50 kg / cm ² ) and the fuel pressure accumulation chamber (common rail) 53 is supplied. The fuel is pumped and fuel is supplied from the pressure accumulation chamber 53 to the fuel injection valve 30 provided for each of the cylinders # 1, # 2, # 3, and # 4. The pressure (fuel pressure) of the fuel supplied to the fuel injection valve 30 is detected by a fuel pressure sensor 56 (detailed later).

  In the high-pressure fuel pump control device 1 of the present embodiment, a control unit 100 incorporating a microcomputer is provided to perform various controls of the engine 10 including the high-pressure fuel pump 60.

  As shown in FIG. 2, the control unit 100 is basically composed of an MPU 101, an EP-ROM 102, a RAM 103, an I / O LSI 104 including an A / D converter, and the like, and an airflow sensor 24 as an input signal. , A signal corresponding to the intake air amount detected by the fuel pressure sensor 56, a signal corresponding to the fuel pressure detected by the fuel pressure sensor 56, a signal corresponding to the opening of the throttle valve 25 detected by the throttle sensor 23, and a signal from the cam angle sensor 36. Detected by a phase (rotation position) detection signal of the exhaust camshaft 49, a rotation angle / phase (rotation position) detection signal of the crankshaft 18 from the crank angle sensor 37, and an air-fuel ratio sensor 44 disposed in the exhaust passage 40. A signal corresponding to, for example, the oxygen concentration in the exhaust gas, and a water temperature sensor 19 disposed in the cylinder block 12 Other corresponding to the engine coolant temperature detected signal, the signal for indicating the beginning of startup from an ignition switch, not shown in FIG. 1 (the start of cranking) is supplied.

  The control unit 100 fetches each signal with a predetermined period, executes a predetermined calculation process, and uses the control signal calculated as the calculation result as each fuel injection valve 30, the ignition coil 34, the high pressure fuel pump 60, the low pressure. The fuel is supplied to the fuel pump 51, the electric throttle valve 25, etc., and fuel injection (injection amount, injection timing) control, ignition timing control, fuel pressure control, opening control of the throttle valve 25, and the like are executed.

  The high-pressure fuel pump control device 1 according to the present embodiment is characterized by output control of a control (drive) signal for an actuator (solenoid 90) provided in the high-pressure fuel pump 60. This will be described in detail.

  FIG. 3 shows the overall configuration of the fuel supply system including the high-pressure fuel pump 60, and FIG. 4 shows an enlarged longitudinal section of the high-pressure fuel pump 60.

  The high-pressure fuel pump 60 pressurizes fuel from the fuel tank 50 and pumps high-pressure fuel into the pressure accumulating chamber 53. The high-pressure fuel pump 60 includes a cylinder chamber 67, a pump chamber 68, and a solenoid chamber 69. The chamber 67 is disposed below the pump chamber 68, and the solenoid chamber 69 is disposed on the suction side of the pump chamber 68.

  The cylinder chamber 67 is provided with a plunger 62, a lifter 63, and a plunger lowering spring 64. The plunger 62 is provided with an exhaust cam shift 49 and a lifter 63 pressed against a pump drive cam 47 that rotates integrally therewith. The volume of the pressurizing chamber 72 is changed.

  The pump chamber 68 includes a suction passage 71 for low-pressure fuel, a pressurization chamber 72, and a discharge passage 73 for high-pressure fuel. Between the suction passage 71 and the pressurization chamber 72, a suction valve serving as a fuel passage valve is provided. 65 is provided. The intake valve 65 is a check valve that restricts the direction of fuel flow, and is biased in the valve closing direction (the direction from the pump chamber 68 toward the solenoid chamber 69) by a valve closing spring 65a. A discharge valve 66 is provided between the pressurizing chamber 72 and the discharge passage 73. The discharge valve 66 is also a check valve that restricts the direction of fuel flow, and is closed by a valve closing spring 66a. Is biased in the direction. The valve closing spring 65a has a pressure on the pressure chamber 72 side equal to or higher than the pressure on the suction passage 71 side with the suction valve 65 sandwiched by the volume change in the pressure chamber 72 by the plunger 62. In this case, the suction valve 65 is urged to close.

  In the solenoid chamber 69, a solenoid 90, which is an actuator, a suction valve operating member 91, and a valve opening spring 92 are disposed. The suction valve operating member 91 is disposed at a position opposite to the suction valve 65. When the solenoid 90 is energized and energized, its tip (rod portion) is brought into contact with and separated from the suction valve 65, and is attracted to the solenoid chamber 69 side by the electromagnetic force. 65 is moved in the valve closing direction. On the other hand, in a state where the solenoid 90 is not energized, the suction valve 65 is opened via the suction valve operating member 91 by the biasing force of the valve opening spring 92 that presses against the rear end of the suction valve operating member 91. The valve is moved in the valve direction and opened.

  The fuel adjusted to a predetermined pressure from the fuel tank 50 via the fuel pump 51 and the fuel pressure regulator 52 is guided to the suction passage 71 of the pump chamber 68, and then, in the pressurizing chamber 72 in the pump chamber 68. The pressure is increased by the reciprocating motion of the plunger 62, and the pressure is fed from the discharge passage 73 of the pump chamber 68 to the pressure accumulating chamber 53.

  The pressure accumulating chamber 53 is provided with a fuel pressure sensor 56, and the control unit 100 controls (drives) the solenoid 90 based on detection signals from the crank angle sensor 37, the cam angle sensor 36, and the fuel pressure sensor 56. ) A signal is output to control the fuel discharge amount of the high-pressure fuel pump 60. A relief valve 57 is arranged between the pressure accumulating chamber 53 and the fuel tank 50 in order to prevent damage to the piping system, and the pressure in the pressure accumulating chamber 53 is predetermined. The valve is opened when the value is exceeded.

  FIG. 5 shows an operation time chart of the high-pressure fuel pump 60. Note that the actual stroke (actual position) of the plunger 62 driven by the pump drive cam 47 is a curve as shown in the lower part of FIG. 6, but in order to make the positions of the top dead center and the bottom dead center easy to understand. In the drawings (FIGS. 5, 9, 10, 17, 18, and 18) other than FIG. 6, the stroke of the plunger 62 is drawn linearly.

  When the plunger 62 moves from the top dead center side to the bottom dead center side according to the biasing force of the plunger lowering spring 64 by the rotation of the pump drive cam 47, the suction stroke of the pump chamber 68 is performed. In this intake stroke, the intake valve operating member 91 moves the intake valve 65 in the valve opening direction in accordance with the biasing force of the valve opening spring 92. Thereby, the pressure in the pressurizing chamber 72 decreases.

  Next, when the plunger 62 moves from the bottom dead center side to the top dead center side against the biasing force of the plunger lowering spring 64 by the rotation of the cam 47, the compression stroke of the pump chamber 68 is performed. In this compression stroke, when the drive signal of the solenoid 90 which is an actuator is output from the control unit 100 and the solenoid 90 is energized and excited (ON state), the suction valve operating member 91 is biased by the valve opening spring 92. The suction valve 65 is moved in the direction to close the valve, the tip of the suction valve 65 is separated from the suction valve 65, and the suction valve 65 moves in the valve closing direction according to the urging force of the valve closing spring 65a. . Thereby, the pressure in the pressurizing chamber 72 rises.

  When the suction valve operating member 91 is most attracted to the solenoid 90 side and the suction valve 65 synchronized with the reciprocation of the plunger 62 is closed to increase the pressure in the pressurizing chamber 72, the pressure in the pressurizing chamber 72 is increased. The fuel presses the discharge valve 66, and the discharge valve 66 is automatically opened against the urging force of the valve closing spring 66 a, and the high pressure fuel corresponding to the volume reduction of the pressurizing chamber 72 enters the accumulator chamber 53 side. Discharged. The energization of the solenoid 90 (output of the drive signal) is stopped (OFF) when the suction valve 65 is moved to the solenoid 90 side and closed, but as described above, the pressurizing chamber 72 is turned off. Since the internal pressure is high, the suction valve 65 is maintained in a closed state, and fuel is discharged to the pressure accumulation chamber 53 side.

  When the plunger 62 moves from the top dead center side to the bottom dead center side according to the biasing force of the plunger lowering spring 64 by the rotation of the cam 47, the suction stroke of the pump chamber 68 is performed, and the pressurizing chamber As the pressure in 72 is reduced, the suction valve operating member 91 is moved in the direction to open the suction valve 65 in accordance with the urging force of the valve opening spring 92, and the suction valve 65 is reciprocated by the plunger 62. The valve is automatically opened in synchronism, and the open state of the intake valve 65 is maintained. The discharge valve 66 is not opened due to the pressure drop in the pressurizing chamber 72. Thereafter, the above operation is repeated.

  Therefore, when the solenoid 90 is turned on (energized excitation state) in the middle of the compression stroke before the plunger reaches the top dead center, the fuel is pumped to the pressure accumulating chamber 53, and the fuel is pumped once. If it starts, the pressure in the pressurizing chamber 72 rises. Therefore, even if the solenoid 90 is turned off thereafter, the suction valve 65 remains closed, but in synchronization with the start of the suction stroke. It can be opened automatically. Therefore, the fuel discharge amount to the pressure accumulating chamber 53 side can be adjusted by the output start timing of the drive signal of the solenoid 90. Further, by setting an appropriate output start timing based on the signal from the pressure sensor 56 and controlling the solenoid 90, the pressure in the pressure accumulating chamber 53 can be feedback controlled to the target value.

  FIG. 7 is a functional block diagram of high-pressure fuel pump control executed by the control unit 100. The control unit 100 includes a basic angle calculation means 701, a target fuel pressure calculation means 702, a fuel pressure input processing means 703, a pump control signal calculation means 750 which is one aspect of a means for calculating a solenoid control signal, and energization excitation of the solenoid 90. Solenoid driving means 707 for outputting a driving signal for this purpose.

  The basic angle calculation means 701 calculates a basic angle BASANG of a solenoid control signal for turning the solenoid 90 into an energized excitation state (ON state) based on the operating state. Here, FIG. 11 shows the relationship between the closing timing of the intake valve 65 and the discharge amount of the high-pressure fuel pump. The basic angle BASANG is used for setting the closing timing (crank angle) of the intake valve 65 for balancing the required fuel injection amount and the high-pressure fuel pump discharge amount. The target fuel pressure calculation means 702 calculates a target fuel pressure Ptarget that is optimal for the operating point based on the operating state. The fuel pressure input processing means 703 filters the signal from the fuel pressure sensor 56 to obtain a measured fuel pressure Preal that is an actual fuel pressure. Then, the pump control signal calculation means 750 calculates a pump control signal (solenoid control signal) based on the basic angle BASANG, the target fuel pressure Ptarget, and the measured fuel pressure Preal. The solenoid driving means 707 outputs a solenoid driving signal for energizing and exciting the solenoid 90 according to the solenoid control signal from the pump control signal calculating means 750 (details will be described later).

  FIG. 8 is a functional block diagram showing a more detailed configuration of the pump control signal calculation means 750. The pump control signal calculation means 750 basically calculates the reference angle calculation means 704 for calculating the output start timing of the drive signal (pulse) of the solenoid 90 and the width of the drive signal (pulse width = energization time). A pump signal energization time calculation unit 706, and a reference angle calculation unit 704 includes a basic angle BASANG calculated by the basic angle calculation unit 701, a target fuel pressure Ptarget calculated by the target fuel pressure calculation unit 702, and a fuel pressure input processing unit. Based on the measured fuel pressure Preal calculated in Step 703, a reference angle REFANG serving as a reference for starting output of the drive signal is calculated.

  Then, the operation delay correction amount PUMRE obtained by the solenoid operation delay correction means 705 is added to the reference angle REFANG to calculate the output start angle STANG of the drive signal of the solenoid 90, and this is calculated as the start of output of the drive signal of the solenoid 90 The timing is sent to the solenoid driving means 707.

  The pump signal energization time calculation means 706 calculates the energization time TPUMKE of the solenoid 90 of the high-pressure fuel pump 60 based on the operating conditions, and sends it to the solenoid drive means 707. The solenoid drive means 707 outputs a drive signal to the solenoid 90 based on the output start angle STANG and the energization time TPUMKE to perform energization excitation. The value of the energization time TPUMKE is a suction valve operating member until the suction valve 65 can be closed by the pressure of the pressurizing chamber 72 even under the worst condition of solenoid suction force generation where the battery voltage is low and the solenoid resistance is large. 91 is set to a value that can reliably close the intake valve 65. Further, the solenoid operation delay correction means 705 calculates the solenoid operation delay correction amount PUMRE based on the battery voltage because the electromagnetic force of the solenoid 90 and thus the operation delay time varies depending on the battery voltage.

  FIG. 9 shows a time chart of high-pressure fuel pump control by the control unit 100. Based on the detection signal from the cam angle sensor 36 (cam angle signal = CAM signal) and the detection signal from the crank angle sensor 37 (crank angle signal = CRANK signal), the control unit 100 controls each cylinder # 1, # 2, The top dead center position of the compression stroke of the piston 15 in # 3, # 4 (CYL1, CYL2, CYL3, CYL4) is detected, fuel injection control and ignition timing control are performed, and the stroke of the plunger 62 is detected to detect high pressure. Output control of the drive signal of the solenoid 90 which is an actuator of the fuel pump 60 is performed. The REF signal used for the high-pressure fuel pump control is generated based on the crank angle signal and the cam angle signal, and the rising point of REF on the high-pressure fuel pump intake stroke that exists every other REF is used as a reference point. Hereinafter, the rise of REF as the reference point is referred to as “reference REF”.

  Here, the portion where the crank angle signal (CRANK signal) is missing (broken line portion) in FIG. 9 is the starting point for phase detection of the crank angle signal and the cam angle signal, and is the starting point of cylinder # 1 (CYL1). The position is shifted from the top dead center or the top dead center of cylinder # 4 (CYL4) by a predetermined phase (crank angle). Then, when the crank angle signal is missing, the control unit 100 determines whether the cam angle signal is Hi (high) or Lo (low), either on the cylinder # 1 (CYL1) side or on the cylinder # 4. It is determined whether it is on the (CYL4) side, and then an initial REF signal is generated. In addition, fuel discharge from the high-pressure fuel pump 60 is started after a lapse of a predetermined time, which is the operation delay PUMRE of the solenoid 90 from the rise of the solenoid drive signal, while this fuel discharge ends when the output of the solenoid drive signal ends. However, since the suction valve 65 is pushed (closed) by the pressure in the pressurizing chamber 72, the stroke of the plunger 62 is continued until the top dead center is reached.

FIG. 10 shows parameters such as the output start angle STANG and energization time TPUMKE of the solenoid drive signal used for the fuel pressure control. The output start angle STANG, which is the output timing of the solenoid drive signal, can be obtained as shown in (Equation 1) below.
STANG = REFANG−PUMRE ……… (Formula 1)

  Here, REFANG is calculated by the reference angle calculation means 704 based on the operating state of the engine 10. PUMRE is a pump delay angle, which is calculated by the solenoid operation delay correction means 705, and represents, for example, the actuator drive time that varies depending on the battery voltage, that is, the operation delay of the intake valve operating member 91 according to the energization amount to the solenoid. . The energization time TPUMKE, which is the width (pulse width) of the drive signal of the solenoid 90, is calculated based on the battery voltage and the operating state (engine speed, etc.).

  Then, the output start angle STANG sets the solenoid drive signal for closing the suction valve 65 from the reference REF, that is, the output start timing of the solenoid drive signal is set, while the energization time TPUMKE sets the solenoid drive signal. How long the drive signal continues to be output, that is, the pulse width of the solenoid drive signal, in other words, the output stop timing of the solenoid drive signal is set. Hereinafter, the control of the solenoid 90 by the output start angle STANG is referred to as “basic control”.

  Therefore, since the REF signal is indispensable for the “basic control”, the control different from the “basic control” is performed until the first reference REF is recognized from the start of the start. This control is referred to as “start control”, and an example of this start control will be described below.

  FIG. 12 is a functional block diagram of an example of the start control executed by the control unit 100. The control unit 100 includes target fuel pressure calculation means 702, fuel pressure input processing means 703, start-up pump control signal calculation means 1201, and solenoid drive means 707 for outputting a drive signal for energizing and exciting the solenoid 90.

  The starting pump control signal calculating means 1201 calculates a solenoid control signal based on each signal from the crank angle sensor 37, the cam angle sensor 36, the fuel pressure sensor 56, the water temperature sensor 19 and the battery voltage.

  FIG. 13 shows a flowchart of processing performed by the starting pump control signal calculating means 1201 and the solenoid driving means 707. In step 1301, interrupt processing starts, but the interrupt processing may be a time cycle, for example, every 10 ms, or a rotation cycle, for example, every 10 degrees of crank angle. In step 1302, it is determined whether or not the reference REF is recognized. If it is before the reference REF is recognized, the process proceeds to step 1303. As described above, after the reference REF is recognized, the mode is switched to “basic control”. In step 1303, it is determined whether or not the drive signal output start flag is “ON”.

  Here, FIG. 14 shows a flowchart of the drive signal output start flag determination process executed in step 1303. The drive signal output start flag is set to “off” in the initial setting (at the start of engine start), and interrupt processing starts in step 1401. In step 1402, it is determined whether or not the crank angle signal (pulse) from the start of start has been recognized a predetermined number of times (A) or more. This is to prevent the malfunction by detecting the noise of the crank angle signal input when the control unit 100 is powered on. Therefore, the predetermined number of times (A) is set to a small number within a range not affected by noise.

  In step 1403, it is determined based on the detection signal from the fuel pressure sensor 56 whether or not the fuel pressure is a predetermined value or less. When the fuel pressure is equal to or higher than the target fuel pressure, if a drive signal is output, the fuel pressure may exceed the target fuel pressure at the start of injection, which may deteriorate combustion. Therefore, the predetermined value in step 1403 is set to the target fuel pressure. If the fuel pressure is less than or equal to the predetermined value, the process proceeds to step 1404. In step 1404, it is determined whether or not the cooling water temperature is equal to or lower than a predetermined value. When the cooling water temperature is equal to or higher than a predetermined value, it indicates that the temperature of the solenoid 90 is high, and if the drive signal is output, the durability of the solenoid 90 may be reduced. In this example, the coolant temperature is used to estimate the temperature of the solenoid 90, but engine oil temperature, fuel temperature, and the like may be used. Further, the temperature of the solenoid 90 may be directly detected. If the cooling water temperature is equal to or lower than the predetermined value, the process proceeds to step 1405. In step 1405, it is determined whether or not a predetermined period has elapsed since the end of output of the previous drive signal. If the predetermined period has elapsed, the drive signal output start flag is set to “ON”.

  Here, FIG. 16 is a functional block diagram showing processing up to the determination of whether or not the predetermined period has elapsed. When the period until the next output start is short, the temperature of the solenoid 90 remains increased, and the durability of the solenoid 90 may be reduced. For this reason, the cooling time of the solenoid 90 is required. Since the time required for cooling is proportional to the temperature of the solenoid 90, that is, the drive signal output time, the cooling time request value is calculated using the previous drive signal output time as an input (block 1601). In addition, since there is a possibility that the discharge stroke may occur twice from the start to the reference REF recognition, after a predetermined crank angle from the end of the output, a request must be made to restart the output at a position where the high pressure fuel pump can fully discharge. . The predetermined crank angle is set as a crank angle request value (FIG. 17) (block 1602), and the crank angle request value is set to be equal to or less than an angle corresponding to one reciprocation of the plunger 62. In block 1603, the larger of the required cooling time value and the required crank angle value is set as the predetermined period.

  If it is determined in step 1303 of FIG. 13 that the drive signal output start flag is “on”, the process proceeds to step 1304 to determine whether or not the drive signal output end flag is “off”.

  Here, FIG. 15 shows a flowchart of the drive signal output end flag determination process executed in step 1304. The drive signal output end flag is set to “OFF” in the initial setting (at the start of engine start), and interrupt processing starts in step 1501. In step 1502, it is determined whether or not the fuel pressure has increased by a predetermined value or more. When the fuel pressure before the unit time (for example, 20 [ms] before) is stored in the RAM 103 and compared with the current fuel pressure, it is determined whether or not the fuel pressure has been increased by a predetermined value or more. Since the high-pressure fuel pump 60 has started discharging, the drive signal output end flag is set to “ON”. The predetermined value is set to a value that maintains the closed state of the intake valve 65 even when the drive signal output is finished.

  In the subsequent step 1503, it is determined whether or not the crank angle signal (pulse) from the start of start has been recognized a predetermined number of times (B) or more. This is performed to end the output of the drive signal when the high pressure fuel pump 60 starts discharging in step 1502 and there is a bubble or the like in the pressure accumulating chamber 53 and pressure increase cannot be recognized. In step 1504, it is determined whether or not a predetermined period has elapsed since the start of driving signal output. This is performed in order to end the output of the drive signal when the engine is stopped before the reference REF is recognized, the pressure is not increased, and the crank angle signal is also stopped. Therefore, the predetermined period from the start of output is set to the longest time required until the reference REF is recognized.

  If it is determined in step 1304 in FIG. 13 that the drive signal output end flag is “off”, the process proceeds to step 1305 to output a solenoid drive signal. The signal output at this time is a continuous signal (duty 100%). This is because when the energization of the solenoid 90 is started and the energization is stopped before the pressure in the pressurizing chamber 72 becomes high, the suction valve 65 may not be reliably closed. In this case, the suction valve 65 is not opened. This is to prevent the high pressure fuel from being discharged to the pressure accumulation chamber 53 side due to the valve state.

  Further, when the drive signal output start flag is “off” in step 1303 described above and when the drive signal output end flag is “on” in step 1304, the output of the solenoid drive signal is prohibited (stopped).

  As described above, in the present embodiment, as shown in the time chart of FIG. 18, in a period from the start of start to the recognition of the reference REF, in other words, the solenoid drive signal is set to a predetermined value from the start of start. Output of the solenoid drive signal is started within a period until the crank angle phase can be output, and when the fuel pressure in the pressure accumulating chamber 53 is increased by a predetermined value or more per unit time, the solenoid drive signal is output. Therefore, the fuel pressure can be surely increased to the required pressure, the robustness to good combustion is improved, and the reference REF is reduced from the start of the start compared to the conventional example. Since the total energization time of the solenoid 90 within the period until it is recognized can be shortened, the durability of the high-pressure fuel pump 60 can be improved. Reduce current consumption, etc. can be achieved.

  In the above embodiment, the timing for stopping the output of the solenoid drive signal is set as when the fuel pressure in the pressure accumulating chamber 53 is increased by a predetermined value or more per unit time. Instead, the output stop is performed. The timing may be set, for example, when the pressure difference from the start of starting becomes a predetermined value or more.

  Next, an example of the start control according to another embodiment of the high pressure fuel pump control device according to the present invention will be described with reference to FIG. In the present embodiment, the high-pressure fuel pump discharge control region start angle (timing) and the high-pressure fuel pump discharge control region end angle are based on signals obtained from the crank angle sensor 37 and the cam angle sensor 36 in the embodiment shown in FIG. A plunger signal for setting (timing) is generated.

  Here, as described above, the drive control of the solenoid 90 is performed in consideration of the operation delay and the operation delay of the suction valve operation member 91 associated therewith. Therefore, the high-pressure fuel pump discharge control region is defined as from the bottom dead center of the plunger 62 to the plunger top dead center from the angle before the operation delay of the intake valve operating member 91. During “startup control”, when the start angle (timing) of the high-pressure fuel pump discharge control region is recognized, output of the solenoid drive signal is started, and output is continued for the energization time TPUMKE of the solenoid 90 to increase the pressure. A crank angle corresponding to TPUMKE may be used instead of the TPUMKE with respect to the energization time.

  In this way, the output start timing of the solenoid drive signal was at the start of start in the above embodiment, but in this embodiment, it is delayed from the start of start, so the total energization time of the solenoid 90 is reduced. Thus, the durability of the high-pressure fuel pump 60 can be improved and the current consumption can be further reduced.

  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 can be done.

  For example, in the above embodiment, the high-pressure fuel pump 60 is driven by the exhaust camshaft 49, but may be driven by the intake camshaft 29 or the crankshaft 18.

DESCRIPTION OF SYMBOLS 1 High pressure fuel pump control apparatus 10 Engine 18 Crankshaft 29 Intake camshaft 30 Fuel injection valve 36 Cam angle sensor 37 Crank angle sensor 47 Pump drive cam 49 Exhaust camshaft 56 Fuel pressure sensor 60 High pressure fuel pump 65 Intake valve (fuel passage valve)
90 Solenoid (actuator)
100 control unit

Claims (2)

A pressurization chamber, a plunger that pressurizes fuel in the pressurization chamber, a fuel passage valve that sucks fuel into the pressurization chamber, and an actuator that operates the fuel passage valve in a valve closing direction by a drive signal. And a control device for a high-pressure fuel pump that pumps fuel into the fuel pressure storage chamber,
In the start control period from the start of starting the high-pressure fuel pump until it becomes possible to output the drive signal at a predetermined crank angle phase, the output of the drive signal is started,
Drive signal control means for prohibiting the output of the drive signal based on the fuel pressure in the fuel accumulator chamber during the start control period ;
The drive signal control means prohibits the output of the drive signal when a predetermined period has elapsed from the start of output of the drive signal or when the crank angle signal is recognized a predetermined number of times. apparatus. The high-pressure fuel pump control device according to claim 1, wherein the drive signal control means sets the predetermined number of times based on a battery voltage.