High-pressure fuel pump control device

Abstract

To provide a control device for a high pressure fuel pump that avoids pulsation of fuel pressure caused by interference between two types of control that are discharge amount control based on electric current start timing and silencing control based on an electric current value.SOLUTION: In an ECU (112) for controlling a high pressure fuel pump (103), a fuel pressure sensor (401) is disposed and a plunger phase measurement section (402) is provided. The ECU includes: a plunger operation determination section (801); a fuel pressure rise evaluation section (802); a valve closing determination section (803); and a discharge amount control section (804) that controls discharge amount of fuel by controlling electric current application start timing to a solenoid (205) on the basis of fuel pressure measured by the fuel pressure sensor (401) and target fuel pressure. The discharge amount control section (804) determines a control gain at the electric current application start timing on the basis of a determination result obtained by the valve closing determination section (803).SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a control device for a high-pressure fuel pump. [Background technology]

[0002] Automotive internal combustion engines are required to be highly efficient, have low emissions, and have high power output. Direct injection internal combustion engines have long been popular as a means of achieving a good balance between these requirements. Automakers and suppliers have made constant efforts to improve the value of their products, and one of the most important challenges is to reduce the noise of high-pressure fuel pumps.

[0003] To make a high-pressure fuel pump quieter, the current driving the pump can be reduced. However, if the current is reduced too much, the high-pressure fuel pump will not be able to discharge fuel. The optimal amount of current to apply for quieter operation varies depending on the individual high-pressure fuel pump.

[0004] In conventional noise reduction control for high-pressure fuel pumps, the minimum amount of current to be applied is determined for each individual high-pressure fuel pump without causing fuel discharge failure, as in Patent Document 1. The technology in Patent Document 1 achieves noise reduction by reducing the current (second current). However, if the current is reduced too much, the valve closing operation will be insufficient, so if the actual fuel pressure in the pressure accumulator vessel drops below the target fuel pressure by more than a predetermined value, the current is increased to resolve the insufficient valve operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-53247 Summary of the Invention [Problem to be solved by the invention]

[0006] Regardless of whether noise reduction control is performed, the high-pressure fuel pump controls the discharge amount so that the fuel pressure follows a target value. In the high-pressure fuel pump, the discharge amount is controlled by controlling the start time of the current applied to the solenoid. Therefore, in a high-pressure fuel pump that supports noise reduction control, two controls are performed in parallel: discharge amount control by the current start timing and noise reduction control by the current value.

[0007] The problem here is that two controls are performed by comparing the measured fuel pressure value with the target fuel pressure, and the interference between the two controls.

[0008] In Patent Document 1, when the measured fuel pressure falls below the target fuel pressure, it is determined that the valve closing operation is insufficient, and the second current value is increased. On the other hand, in discharge amount control, when the measured fuel pressure falls below the target fuel pressure, the timing to start applying current is advanced to increase the discharge amount. The two values ​​are controlled without distinguishing whether the cause of the measured fuel pressure falling below the target fuel pressure is the current value or the timing to start applying current.

[0009] Furthermore, if the valve closing malfunction occurs, the fuel pressure will fall below the target value. This will cause the current application start timing to be earlier than the desired timing, even though it would be possible to achieve a sufficient discharge volume. This earlier current application start timing will cause unnecessary fuel pressure pulsation.

[0010] An object of the present invention is to provide a control device for a high-pressure fuel pump that avoids fuel pressure pulsation due to interference between two controls: discharge amount control based on current start timing and noise reduction control based on current value. [Means for solving the problem]

[0011] a plunger operation determination unit that determines whether the plunger is rising based on the phase angle of the plunger; a fuel pressure rise evaluation unit that evaluates a rise in fuel pressure during a period in which it is determined that the plunger is rising by the plunger operation determination unit; a valve closure determination unit that determines whether the intake valve is closed based on the evaluation result of the fuel pressure rise evaluation unit; and a discharge amount control unit that controls a discharge amount of fuel by controlling a start timing of application of current to the solenoid based on the fuel pressure measured by the fuel pressure sensor and a target fuel pressure, wherein the discharge amount control unit determines a control gain for the start timing of application of current based on the determination result of the valve closure determination unit. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a control device for a high-pressure fuel pump that avoids fuel pressure pulsation due to interference between two controls: discharge amount control based on current start timing and noise reduction control based on current value. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an internal combustion engine according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the high-pressure fuel pump according to the first embodiment. [Figure 3] FIG. 3 is a time chart showing the operation of the high-pressure fuel pump according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing the high-pressure fuel pump according to the first embodiment. [Figure 5A]FIG. 5A is an explanatory diagram showing the operation of the valve element when the valve is successfully closed according to the first embodiment. [Figure 5B] FIG. 5B is an explanatory diagram showing the operation of the valve body when the valve fails to close according to the first embodiment. [Figure 6] FIG. 6 is a conceptual diagram showing a method for determining whether the valve has been closed successfully from the rise in fuel pressure synchronized with the rise of the plunger according to the first embodiment. [Figure 7] FIG. 7 is an explanatory diagram showing the change in fuel pressure when the present invention is not applied. [Figure 8] FIG. 8 is a block diagram showing the high-pressure fuel pump and each control unit of the ECU according to the first embodiment. [Figure 9] FIG. 9 is a flowchart showing the noise reduction control (current application amount control) executed every 2 ms according to the first embodiment. [Figure 10] FIG. 10 is a flowchart showing the discharge amount control executed every 10 ms according to the first embodiment. [Figure 11] FIG. 11 is an explanatory diagram showing how pressure pulsation is reduced according to the first embodiment. [Figure 12] FIG. 12 is a block diagram showing a high-pressure fuel pump according to the second embodiment. [Figure 13] FIG. 13 is an explanatory diagram showing a map representing the correlation between the target fuel pressure and the current application timing according to the second embodiment. [Figure 14] FIG. 14 is a flowchart showing interference reduction control between discharge amount control and noise reduction control (first current application amount control) according to the operating state of the internal combustion engine according to the second embodiment. [Figure 15] FIG. 15 is a block diagram showing a high-pressure fuel pump according to the fourth embodiment. [Figure 16] FIG. 16 is an explanatory diagram showing a map for adjusting the correlation between the current application timing and the current application amount stored in the current parameter memory according to the fourth embodiment through learning for each individual. [Figure 17] FIG. 17 is a flowchart showing interference reduction control between discharge amount control according to the learning state of the internal combustion engine and noise reduction control (first current application amount control) according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention should not be construed as being limited to the following embodiments, and the technical concept of the present invention may be realized by combining other known components. Note that the same elements in each drawing are designated by the same reference numerals, and redundant explanations will be omitted. In each drawing, the U direction is the upward direction, the D direction is the downward direction, the R direction is the rightward direction, and the L direction is the leftward direction.

[0015] First Embodiment In this embodiment, the valve element is open when no current is applied to the solenoid. When current is applied to the solenoid, the valve element closes, preventing fuel compressed by the rising plunger from returning to the low-pressure pipe and discharging the fuel into the high-pressure pipe. This embodiment describes a normally open pump that operates in this manner. However, this embodiment can also be applied to a normally closed pump by exchanging the closed and open valves.

[0016] <<Overview of the internal combustion engine 100>> FIG. 1 is a schematic diagram showing an internal combustion engine 100 according to this embodiment. FIG. 1 shows an outline of a direct-injection internal combustion engine as the internal combustion engine 100. In the internal combustion engine 100, fuel stored in a fuel tank 101 is pressurized to about 0.4 MPa by a feed pump 102, and is further pressurized to several tens of MPa by a high-pressure fuel pump 103 via a low-pressure pipe 111. The pressurized fuel passes through a high-pressure pipe 104 and is injected from a direct-injection injector 105 into a cylinder 106 of the internal combustion engine 100.

[0017] The injected fuel is mixed with air drawn into cylinder 106 by the movement of piston 107. This mixture is ignited by a spark generated by spark plug 108, causing an explosion. The heat generated by the explosion causes the mixture in cylinder 106 to expand, pushing piston 107 down. The force pushing piston 107 down is transmitted via link mechanism 109 to rotate crankshaft 110. The rotation of crankshaft 110 is transmitted to the wheels via the transmission, providing the force to move the vehicle.

[0018] The internal combustion engine 100 is controlled by an ECU (engine control unit) 112, which is a control device. The ECU 112 is a microcontroller that comprehensively controls electrical auxiliary devices when the operation of the internal combustion engine 100 is controlled using these devices. The ECU 112 constitutes a functional unit formed by the cooperation of, for example, a program and a computing device. The ECU 112 is a control device that controls the high-pressure fuel pump 103.

[0019] The main requirements for an internal combustion engine 100 are low fuel consumption, high power output, and exhaust purification, but additional value is also required from the engine by reducing noise and vibration. In the high-pressure fuel pump 103, noise is generated when the valve body or anchor 204 hits the stopper 208 when the intake valve 203 opens and closes. Automobile manufacturers and suppliers are making great efforts to reduce noise.

[0020] <<Configuration of high-pressure fuel pump 103>> Fig. 2 is a schematic diagram showing the configuration of the high-pressure fuel pump 103 according to this embodiment. Fig. 2 shows the structure of the high-pressure fuel pump 103. The high-pressure fuel pump 103 includes a plunger 202 that moves up and down with the rotation of a cam 201 attached to the crankshaft 110 of the internal combustion engine 100. The plunger 202 compresses the fuel in a pressurizing chamber 211.

[0021] The high-pressure fuel pump 103 includes an intake valve 203 that opens and closes in synchronization with the up and down movement of a plunger 202. The intake valve 203 is disposed between the low-pressure pipe 111 and the pressurizing chamber 211, between the low-pressure pipe 111 and the high-pressure pipe 104, in order to pressurize and discharge the fuel in the low-pressure pipe 111 into the high-pressure pipe 104.

[0022] The high-pressure fuel pump 103 includes a solenoid 205 that controls the opening and closing operation of the intake valve 203. The high-pressure fuel pump 103 includes an anchor 204 that is attracted by the electromagnetic force generated by the solenoid 205 and controls the operation of the intake valve 203.

[0023] High-pressure fuel pump 103 is surrounded by a casing 223, and defines a pressurized chamber 211 therein. Fuel flows into pressurized chamber 211 from the low-pressure piping 111 side through inlet 225 and communication port 221. The fuel that flows into pressurized chamber 211 is discharged to the high-pressure piping 104 side through outlet 222. Outlet 222 is opened and closed by discharge valve 210. Discharge valve 210 is constantly biased by spring portion 226 in a direction that closes outlet 222, and when the pressure in pressurized chamber 211 overcomes the spring force of spring portion 226, outlet 222 opens and fuel is injected.

[0024] In the high-pressure fuel pump 103, the axial movement of the anchor 204 (left and right direction in FIG. 2 ) is controlled by controlling the on / off state of the energized solenoid 205. When the energization of the solenoid 205 is off, the anchor 204 is constantly urged in the valve opening direction by the first spring 209, thereby maintaining the intake valve 203 in the open position. This type of high-pressure fuel pump 103 is called a normally open type high-pressure fuel pump, and the normally open type will be described in this embodiment. However, the high-pressure fuel pump 103 can also be applied to a normally closed type high-pressure fuel pump by interchangeably switching the open and closed valves.

[0025] When solenoid 205 is energized, an electromagnetic attractive force is generated between fixed portion (magnetic core) 206 and anchor 204. As a result, anchor 204, which is provided on the base end side of intake valve 203, is attracted in the valve opening direction (leftward direction L in FIG. 2 ) against the spring force of first spring 209. When anchor 204 is attracted to fixed portion 206, intake valve 203 functions as a check valve that opens and closes based on the pressure difference between the upstream and downstream sides and the biasing force of second spring 215. Therefore, an increase in pressure downstream of intake valve 203 moves intake valve 203 in the valve closing direction. When intake valve 203 moves a set lift amount in the valve closing direction, it seats on seat portion 207, and intake valve 203 is in a closed state, preventing fuel from flowing back into pressurized chamber 211 toward low-pressure pipe 111.

[0026] <<Operation time chart of high-pressure fuel pump 103>> 3 is a time chart showing the operation of high-pressure fuel pump 103 according to this embodiment. In order for intake valve 203 to open and close in synchronization with the up and down movement of plunger 202, the rotation angle of cam 201 attached to crankshaft 110 is detected, and after crankshaft 110 has rotated a predetermined angle (P-ON timing) from top dead center (TDC), for example, voltage V begins to be applied to both ends of solenoid 205 (timing t1). This voltage V causes current I flowing through solenoid 205 to be LdI / dt=V-RI (Equation 1) where L and R are the inductance and resistance of the solenoid 205 and the wiring, respectively. As the current I increases, the magnetic attraction force Fmag with which the fixed part (magnetic core) 206 attracts the anchor 204 also increases.

[0027] When the magnetic attractive force Fmag becomes larger than the force Fsp of the first spring 209, the anchor 204, which has been pressed down by the spring force Fsp, starts to move toward the fixed part 206 (timing t2). When the anchor 204 moves, the intake valve 203 is pushed by the fuel pressurized by the rise of the plunger 202, and moves toward the fixed part 206 following the anchor 204.

[0028] Then, the current I decreases (timing t3). Between timing t2 and timing t3, there is a period Th during which the current I is applied at its maximum value.

[0029] Eventually, the protrusion of intake valve 203 collides with and seats on seat portion 207. This collision blocks the fuel flow path (dotted line in FIG. 2), preventing the fuel pressurized by the rise of plunger 202 from returning to low-pressure pipe 111, and the pressure in pressurizing chamber 211 rises (timing t4).

[0030] When the pressure in the pressurizing chamber 211 becomes greater than the spring force Fsp_out that holds down the discharge valve 210, the discharge valve 210 opens, and the pressurized fuel is discharged into the high-pressure pipe 104 as the plunger 202 rises. After that, when the drive pulse is turned OFF at timing t5, a reverse voltage is applied to the solenoid 205, and the holding current that had been supplied to the solenoid 205 is thereby cut off.

[0031] When the cam angle passes top dead center and the plunger 202 starts to descend (timing t6), the fuel pressure in the pressurizing chamber 211 decreases, and when the fuel pressure becomes smaller than the spring force Fsp_out, the discharge valve 210 closes and the discharge of fuel ends.

[0032] Furthermore, due to the drop in fuel pressure in pressurizing chamber 211, anchor 204 moves from the valve closed position to the valve open position together with intake valve 203 (timing t7 to t8).

[0033] By this operation, high-pressure fuel pump 103 sends fuel from low-pressure pipe 111 to high-pressure pipe 104. During this process, noise is generated when anchor 204 collides with fixed portion 206 to complete valve closing (timing t4 in FIG. 3), and when anchor 204 and suction valve 203 collide with stopper 208 to complete valve opening (timing t8 in FIG. 3). This noise can be unpleasant for the driver, especially when the engine is idling, and automobile manufacturers and suppliers of high-pressure fuel pump 103 are competing to reduce this noise. The present embodiment aims to reduce the noise when anchor 204 and suction valve 203 complete valve closing.

[0034] <<Peak current and holding current>> The current driving the high-pressure fuel pump 103 is roughly divided into two parts: a peak current (the diagonally shaded portion of the current waveform in FIG. 3 ) and a holding current (the horizontally shaded portion of the current waveform in FIG. 3 ). The peak current provides momentum for closing the intake valve 203 and anchor 204, which are held in the open position by the first spring 209. On the other hand, the holding current attracts the anchor 204, which approaches the fixed portion 206, until it collides with the fixed portion 206. After the anchor 204 collides with the fixed portion 206, it maintains contact. Reducing the amount of peak current application weakens the momentum of the intake valve 203 and anchor 204 as they close, thereby reducing noise. However, reducing the amount of peak current application too much can result in failure of the intake valve 203 and anchor 204 to close. Therefore, it is desirable to reduce the amount of peak current application as much as possible while still closing the intake valve 203 and anchor 204. As shown in FIG. 3, the maximum current value of the peak current is Im, and the maximum current value of the holding current is Ik.

[0035] <<Discharge volume control>> FIG. 4 is a block diagram showing a high-pressure fuel pump 103 according to the first embodiment. The role of the high-pressure fuel pump 103 is to compress fuel in the low-pressure pipe 111 and discharge it into the high-pressure pipe 104 so as to maintain the fuel pressure in the high-pressure pipe 104 at a target value. To achieve this, the fuel pressure in the high-pressure pipe 104 is measured by a fuel pressure sensor 401, and a discharge amount control unit 403 controls the timing at which current application starts (P-ON timing) according to the block diagram shown in FIG. 4 so that the measured fuel pressure follows the target fuel pressure. Controlling the timing at which current application starts (P-ON timing) is discharge amount control. In discharge amount control, if the measured fuel pressure is lower than the target fuel pressure, the P-ON timing is advanced to increase the discharge amount discharged into the high-pressure pipe 104. In discharge amount control, if the measured fuel pressure is higher than the target fuel pressure, the P-ON timing is delayed to reduce the discharge amount discharged into the high-pressure pipe 104. PID control is generally used for discharge amount control.

[0036] In some cases, the cam 201 near the plunger 202 is provided with a plunger phase measuring unit 402 that measures the phase angle of the plunger 202 .

[0037] <<Silence control (current application amount control)>> 5A is an explanatory diagram showing the operation of the valve disc when the valve is successfully closed according to this embodiment, and FIG. 5B is an explanatory diagram showing the operation of the valve disc when the valve is unsuccessfully closed according to this embodiment. As described above in <<Peak Current and Holding Current>>, when the peak current application amount is reduced, the speed at which the valve disc of the suction valve 203 closes is reduced, thereby achieving quieter operation.

[0038] The more the peak current is reduced, the quieter the system becomes, but if the peak current is reduced too much, the suction valve 203 and anchor 204 will fail to close. If a sufficient peak current is applied, the valve disc of suction valve 203 will move as shown in Figure 5A. However, if an insufficient peak current is applied, the valve disc of suction valve 203 will succumb to the spring force of first spring 209 and will fail to close as shown in Figure 5B.

[0039] 6 is a conceptual diagram showing a method for determining whether intake valve 203 has closed successfully from the increase in fuel pressure synchronized with the rise of plunger 202 according to this embodiment. If intake valve 203 closes successfully, the valve element of intake valve 203 blocks the flow path from pressurization chamber 211 to low-pressure pipe 111, and the pressure increase caused by the rise of plunger 202 is transmitted to high-pressure pipe 104. As a result, the pressure in high-pressure pipe 104 rises in synchronization with the rise of plunger 202, as indicated by the shaded area in FIG. 6. On the other hand, if intake valve 203 fails to close, fuel in pressurization chamber 211 escapes to low-pressure pipe 111 even if plunger 202 rises, and the pressure in high-pressure pipe 104 does not rise, as indicated by the shaded area in FIG. 6.

[0040] This difference is identified based on the measurement value of the fuel pressure sensor installed in the high-pressure pipe 104 or the common rail, and if the intake valve 203 fails to close, the amount of current applied is increased, and if the intake valve 203 closes successfully, the amount of current applied is reduced, and this process is repeated.

[0041] In this way, by determining whether the intake valve 203 has closed successfully or not based on the fuel pressure fluctuations synchronized with the up and down movement of the plunger 202 and increasing or decreasing the amount of current applied, it is possible to control the current near the minimum amount of current applied that will close the intake valve 203. This current control is noise reduction control. The noise reduction control can reduce the noise generated when the high-pressure fuel pump 103 closes.

[0042] <<Interference between noise reduction control and discharge volume control>> Fig. 7 is an explanatory diagram showing the change in fuel pressure when the present invention is not applied. Fig. 7 shows the relationship between the fuel pressure in the high-pressure pipe 104, the current application start timing P-ON, and the amount of applied current when the discharge amount control and noise reduction control are applied to the high-pressure fuel pump 103.

[0043] 7, the fuel pressure pulsates at a cycle of 37.5 ms up to around 150 ms. The reason for this pulsation is that when intake valve 203 is successfully closed, the pressure increase caused by plunger 202 rising is transmitted to high-pressure pipe 104, while the pressure in high-pressure pipe 104 repeatedly drops due to fuel injection from direct injector 105.

[0044] However, at 187.5 ms, 37.5 ms after 150 ms, no increase in fuel pressure is observed. This is because the intake valve 203 fails to close, and the increase in fuel pressure caused by the rise of the plunger 202 escapes to the low-pressure pipe 11 side and is not transmitted to the high-pressure pipe 104. By observing this change, it is possible to determine whether the intake valve 203 has closed successfully.

[0045] The amount of applied current at this time gradually decreases while the intake valve 203 is successfully closed up to 150 ms, but increases in the cycle from 150 ms to 187.5 ms because a failure to close the intake valve 203 is detected.

[0046] On the other hand, it can be seen that the timing at which current application starts is suddenly advanced around 200 ms. This is because the discharge amount control judges that the fuel pressure drop is due to the late timing at which current application starts, when the fuel pressure drop is caused by the intake valve 203 failing to close due to an excessive reduction in the amount of applied current. Then, the discharge amount control advances the timing at which current application starts to compensate for the drop in fuel pressure.

[0047] This phenomenon is called interference between noise reduction control and discharge amount control, and this embodiment provides a solution to this interference.

[0048] <<Interference reduction control>> In order to reduce the interference between the discharge amount control and the silencing control described above, the ECU 112 performs coordinated control of the discharge amount control and the silencing control (hereinafter referred to as interference reduction control). Here, the discharge amount control is performed at a cycle of 10 ms. The silencing control is performed at a cycle of 2 ms. Although the cycle is not necessarily limited to this cycle, the silencing control must be performed at a cycle short enough to detect the pulsation of the fuel pressure synchronized with the rise of the plunger 202. Furthermore, the cycle of the discharge amount control does not need to be as short as the cycle of the silencing control. The cycle of the discharge amount control may be matched to the cycle of the silencing control to simplify the software, but it must be taken into consideration that this increases the calculation load.

[0049] 8 is a block diagram showing the high-pressure fuel pump 103 according to this embodiment and each control unit of the ECU 112. The high-pressure fuel pump 103 is controlled by the ECU 112.

[0050] Fuel pressure sensor 401 is disposed in high-pressure pipe 104. Cam 201 near plunger 202 is provided with plunger phase measurement unit 402 that measures the phase angle of plunger 202. Plunger phase measurement unit 402 is a rotation angle sensor that detects the rotation angle of cam 201, and measures the phase of plunger 202 from the rotation angle of cam 201.

[0051] ECU 112 includes a plunger operation determination unit 801 that determines that plunger 202 is rising based on the phase angle of plunger 202. ECU 112 includes a fuel pressure increase evaluation unit 802 that evaluates the increase in fuel pressure during the period in which plunger operation determination unit 801 determines that plunger 202 is rising. ECU 112 includes a valve closing determination unit 803 that determines whether intake valve 203 has been closed based on the evaluation result of fuel pressure increase evaluation unit 802.

[0052] ECU 112 includes a discharge amount control unit 804 that controls the amount of fuel discharged by controlling the timing at which current application to solenoid 205 starts based on the fuel pressure measured by fuel pressure sensor 401 and the target fuel pressure. Discharge amount control unit 804 determines a control gain for the timing at which current application starts based on the determination result of valve closing determination unit 803. That is, when the determination result of valve closing determination unit 803 indicates a valve closing failure, discharge amount control unit 804 reduces the control gain for the timing at which current application starts.

[0053] Specifically, when the determination result of valve closing determination unit 803 is a valve closing failure, discharge amount control unit 804 controls the current application start timing to be earlier based on a predetermined relationship between fuel pressure and current application start timing. In other words, discharge amount control unit 804 controls the control gain of the current application start timing to be earlier based on the determination result of valve closing determination unit 803 in the immediately preceding control cycle in which current application amount control unit 805 controls the amount of current to be applied to the solenoid.

[0054] The ECU 112 includes a current application amount control unit 805 that controls the amount of current applied to the solenoid 205 based on the determination result of the valve closing determination unit 803 .

[0055] <<Interference reduction control processing flow>> <<Silencing control process flow>> FIG. 9 is a flowchart showing the noise reduction control executed every 2 ms according to this embodiment.

[0056] First, when an interruption occurs at a 2 ms cycle, the ECU 112 calculates the phase angle of the plunger 202 of the high-pressure fuel pump 103 using the plunger phase measurement unit 402 based on the crank angle calculated from the crank angle sensor and the phase difference between the cam angle and the crank angle from the variable valve mechanism control device (step 901).

[0057] The plunger operation determination unit 801 of the ECU 112 determines whether the plunger phase angle reaches the start angle of a preset fuel pressure change calculation range (step 902). If the plunger phase angle reaches the start angle of the preset fuel pressure change calculation range in step 902, the process proceeds to step 903. If the plunger phase angle does not reach the start angle of the preset fuel pressure change calculation range in step 902, the process proceeds to step 904.

[0058] The fuel pressure increase evaluation unit 802 of the ECU 112 sets the fuel pressure measurement value to the fuel pressure at the start of the increase (step 903). After the processing of step 903, the ECU 112 waits for the next 2 ms interrupt.

[0059] Meanwhile, plunger operation determination unit 801 of ECU 112 determines whether the phase angle of plunger 202 has reached the end angle of a preset fuel pressure change calculation range (step 904). If the plunger phase angle has reached the end angle of the preset fuel pressure change calculation range in step 904, the process proceeds to step 905. If the plunger phase angle has not reached the end angle of the preset fuel pressure change calculation range in step 904, after processing step 904, ECU 112 waits for the next 2 ms interrupt.

[0060] The fuel pressure increase evaluation unit 802 of the ECU 112 sets the fuel pressure measurement value to the fuel pressure at the end of the increase (step 905).

[0061] After the processing of step 905, the fuel pressure increase evaluation unit 802 of the ECU 112 calculates a fuel pressure increase value by subtracting the fuel pressure at the start of the increase set in steps 903 and 905 from the fuel pressure at the end of the increase (step 906).

[0062] The valve closing determination unit 803 of the ECU 112 determines whether the fuel pressure increase value calculated in step 906 is greater than a threshold value (step 907). If the fuel pressure increase value is greater than the threshold value in step 907, the process proceeds to step 908, where it is determined that the valve closing was successful (step 908). After processing step 908, the process proceeds to step 910. If the fuel pressure increase value is not greater than the threshold value in step 907, the process proceeds to step 909, where it is determined that the valve closing was unsuccessful (step 909). After processing step 909, the process proceeds to step 911.

[0063] If the valve closing is successful (step 908), the current application amount control unit 805 of the ECU 112 reduces the current application amount (step 910). If the valve closing is unsuccessful (step 909), the current application amount control unit 805 increases the current application amount (step 911). After the processes of steps 910 and 911, the ECU 112 waits for the next 2 ms interrupt.

[0064] In this way, by executing the silencing control at 2 ms intervals, the amount of current applied is controlled to be close to the minimum value that allows the valve to be closed successfully, thereby achieving silencing.

[0065] <<Discharge volume control process flow>> 10 is a flowchart showing the discharge amount control executed every 10 ms according to this embodiment. The discharge amount control is performed in 10 ms cycles.

[0066] When an interruption occurs at a 10 ms cycle, the discharge amount control unit 804 of the ECU 112 determines whether or not the valve closing was successful in the most recent valve closing determination in the silencing control, which is performed at a 2 ms cycle (step 1001). The discharge amount control unit 804 of the ECU 112 selects the gain of the fuel pressure feedback depending on whether or not the valve closing was successful in step 1001.

[0067] If the discharge amount control unit 804 of the ECU 112 determines in step 1001 that the valve closing is successful, the process proceeds to step 1002. The discharge amount control unit 804 of the ECU 112 selects a feedback gain for the successful case (step 1002).

[0068] If the discharge amount control unit 804 of the ECU 112 determines in step 1001 that the valve closing has failed, the process proceeds to step 1003. In order to prevent the timing of starting current application from being excessively advanced even when there is no problem with discharge amount control, the discharge amount control unit 804 of the ECU 112 selects a feedback gain for failure that is smaller than the feedback gain for success (step 1003).

[0069] Next, the discharge amount control unit 804 of the ECU 112 reads the fuel pressure sensor signal, which is the fuel pressure, from the fuel pressure sensor 401 (step 1004). After the processing of step 1004, the ECU 112 proceeds to the processing of step 1005.

[0070] Then, the discharge amount control unit 804 of the ECU 112 controls the timing of starting current application by, for example, PID control using the previously determined gain in accordance with the difference between the fuel pressure read in step 1004 and the target fuel pressure (step 1005). After processing step 1005, the ECU 112 waits for an interruption of 10 ms.

[0071] <<Effects of this embodiment>> FIG. 11 is an explanatory diagram showing the reduction in pressure pulsation according to this embodiment. According to this embodiment, the feedback gain of the discharge amount control when the valve closing failure occurs can be reduced. This makes it possible to prevent the current application start timing from being excessively advanced. FIG. 11 shows an example of the fuel pressure, applied current amount, and current application start timing when this control is applied. Compared to FIG. 7 before the application of this embodiment, the excessive advance in the current application start timing 187.5 ms after the valve closing failure is detected is prevented. This shows that the non-pulsation of the fuel pressure can be reduced.

[0072] <<Second embodiment: Quieting pump noise during idling>> In this embodiment, noise reduction limited to when the operating state of the internal combustion engine 100 is in an idle state will be described. When the operating state of the internal combustion engine 100 is in an idle state, noises other than those from the high-pressure fuel pump 103 are small. Therefore, the operating sound of the high-pressure fuel pump 103 is noticeable. For this reason, there is a need to perform noise reduction control limited to when the operating state is in an idle state. Therefore, the amount of current applied to the solenoid 205 is controlled only when the operating state of the internal combustion engine 100 is determined to be in an idle state.

[0073] <<Quietness Control When the Internal Combustion Engine 100 is in an Idle State>> FIG. 12 is a block diagram showing the high-pressure fuel pump 103 according to this embodiment. The ECU 112 includes a first current application amount control unit (current application amount control unit in the first embodiment) 1201 that controls the amount of current applied to the solenoid 205 only when it is determined that the operating state of the internal combustion engine 100 is an idle state. Specifically, the first current application amount control unit 1201 executes first current control that controls the amount of current applied to the solenoid 205 based on the determination result of the valve closing determination unit 803. The ECU 112 includes a second current application amount control unit 1202 that executes second current control that controls the amount of current applied to the solenoid 205 based on a predetermined relationship between a target fuel pressure and a current application start timing. The ECU 112 includes an idle determination unit 1203 that determines whether the operating state of the internal combustion engine 100 is an idle state. When it is determined that the operating state of the internal combustion engine 100 is an idle state, the ECU 112 executes noise reduction control (first current control) using the first current application amount control unit 1201. When it is determined that the operating state of the internal combustion engine 100 is not an idle state, the ECU 112 causes the second current application amount control section 1202 to execute the second current control.

[0074] The configuration of this embodiment adds an idle determination unit 1203 that determines whether the operating state of the internal combustion engine 100 is an idle state to the configuration shown in Fig. 8. Also, a current parameter memory 1204 that stores current parameters of a second current application amount control unit 1202 for controlling the current application amount with predetermined current parameters without performing silencing control when the operating state of the internal combustion engine 100 is other than an idle state is added.

[0075] <<Current parameter memory 1204>> 13 is an explanatory diagram showing a map representing the correlation between the target fuel pressure and the current application timing according to the second embodiment. The map of current parameters shown in FIG. 13 is a map representing the correlation between the target fuel pressure and the current application timing that has been obtained in advance through experiments or the like, and is stored in current parameter memory 1204.

[0076] The current parameter map shows a tendency for the current application start timing to be earlier when the target fuel pressure is high and for the current application start timing to be later when the target fuel pressure is low. Second current application amount control unit 1202 of ECU 112 determines the current application start timing according to the target fuel pressure using the current parameter map as the second current control. According to the current parameter map, the current application start timing is controlled to be earlier when the measured fuel pressure is lower than the target fuel pressure and is controlled to be later when the measured fuel pressure is higher than the target fuel pressure.

[0077] <<Interference reduction control processing flow>> FIG. 14 is a flowchart showing interference reduction control between the discharge amount control according to the operating state of the internal combustion engine and noise reduction control (first current application amount control) according to this embodiment.

[0078] When a time interruption (typically 10 ms) occurs, the idle determination unit 1203 of the ECU 112 determines whether the internal combustion engine 100 is in an idle state based on an idle signal from the ECU 112, the engine speed, the load, etc. (step 1401). If the determination result in step 1401 is that the internal combustion engine 100 is in an idle state, the process proceeds to step 1402. If the determination result in step 1401 is that the internal combustion engine 100 is not in an idle state, the process proceeds to step 1403.

[0079] If the determination result in step 1401 is an idle state, noise reduction control is performed in 2 ms cycles by first current application amount control unit 1201 shown in Fig. 9 (step 1402), and discharge rate control is performed in 10 ms cycles as shown in Fig. 10 (step 1403). This processing flow is the same as in the first embodiment, so noise reduction control is performed based on the valve closure detection result, and the gain of the discharge rate control is suppressed when the valve is closed.

[0080] If the determination result in step 1401 is other than an idle state, discharge rate control is performed every 10 ms (step 1403). Meanwhile, second current control is performed by second current application amount control unit 1202 (step 1404). Here, noise reduction control is not performed, and second current application amount control is performed based on current parameter memory 1204, and feedback control based on fuel pressure when plunger 202 rises is not performed.

[0081] <<Effects of this embodiment>> According to this embodiment, noise reduction control can be executed only when the operating state of the internal combustion engine 100 is in an idle state. When noise reduction control is executed, valve closing failure occurs at a certain frequency. However, valve closing failure causes fuel pressure pulsation. When the operating state of the internal combustion engine 100 is in an idle state, the influence of fuel pressure pulsation is reduced. Therefore, by limiting the execution of noise reduction control to when the operating state of the internal combustion engine 100 is in an idle state, the influence of pulsation can be suppressed to an acceptable level.

[0082] <<Third Embodiment>> In the first embodiment, the discharge amount control unit 804 reduces the feedback gain when it is determined that the valve has failed to close, thereby reducing unnecessary advancement of the current application start timing due to a drop in fuel pressure caused by a valve failure due to excessive throttling of the current for noise reduction control.

[0083] In this embodiment, instead, when a valve closing failure is recognized, the timing to start applying current is stored as a map of the target fuel pressure, and fuel pressure feedback is not performed.

[0084] <<Effects of this embodiment>> According to this embodiment, when a valve closing failure is recognized, the current application start timing is stored as a map of the target fuel pressure, and fuel pressure feedback is not performed. Therefore, when a valve closing failure is recognized, control is performed using a simple map, which prevents excessive advancement of the current application start timing and reduces fuel pressure pulsation.

[0085] <<Fourth Embodiment>> In the first embodiment, valve closure is detected based on a rise in fuel pressure synchronized with the plunger 202, and the amount of applied current is gradually reduced while the valve is successfully closed, and increased if the valve fails to close, thereby adapting the amount of applied current to each individual valve. In the method of the first embodiment, the amount of applied current is maintained near the minimum amount of applied current for each individual valve by intentionally causing valve closing failures at a certain frequency. However, there are cases in which fuel pressure pulsation due to valve closing failures using the method of the first embodiment cannot be tolerated.

[0086] In such cases, it is desirable to learn the minimum current application amount required to close the pump when the key is turned on, control the pump with the minimum current value based on this learning, and change the feedback gain so that the current application start timing P-ON does not occur earlier than necessary if the valve fails to close due to a disturbance such as a fuel pressure fluctuation.

[0087] <<Noise reduction control based on learning period>> FIG. 15 is a block diagram illustrating a high-pressure fuel pump 103 according to this embodiment. The ECU 112 includes a first current application amount control unit (current application amount control unit in the first embodiment) 1201 that executes noise reduction control (first current control) to control the amount of current applied to the solenoid 205 based on the determination result of the valve closing determination unit 803. The ECU 112 also includes a third current application amount control unit 1501 that executes third current control to control the amount of current applied to the solenoid 205 based on a predetermined relationship between the current application start timing and the current application amount. The third current control does not perform feedback control based on the fuel pressure when the plunger 202 rises, but instead determines the amount of current application according to the current application start timing using a current parameter map stored in a current parameter memory 1503. The ECU 112 also includes a learning period determination unit 1502 that determines whether a learning period is currently being used to learn the minimum valve closing current application amount of the high-pressure fuel pump 103. During the learning period, the ECU 112 executes noise reduction control using the first current application amount control unit 1201. Except for the learning period, the ECU 112 acquires the determination result of the valve closing determination unit 803 at predetermined intervals, and executes the third current control by the third current application amount control unit 1501 based on the acquired determination result.

[0088] The configuration of this embodiment adds a learning period determination unit 1502 that determines whether the operating state of the internal combustion engine 100 is in a learning period to the configuration of Fig. 8. Also, a current parameter memory 1503 that stores current parameters of a third current application amount control unit 1501 for controlling the current application amount with predetermined current parameters without performing silencing control when not in the learning period is added.

[0089] <<Current parameter memory 1503>> 16 is an explanatory diagram showing a map for adjusting, by individual learning, the correlation between the current application start timing and the current application amount stored in the current parameter memory 1503 according to this embodiment. The current parameter map shown in FIG. 16 is a map for adjusting, by individual learning, the correlation between the current application start timing and the current application amount obtained in advance through an experiment or the like, and is stored in the current parameter memory 1503.

[0090] The current parameter map shows multiple characteristic lines that indicate a tendency for the current application amount to be low when the current application start timing is high and for the current application amount timing to be high when the current application start timing is low. These characteristic lines that indicate this tendency are used by moving them mainly in the direction of the current application amount in accordance with learning for each individual vehicle. As the third current control, the third current application amount control unit 1501 of the ECU 112 determines the current application amount according to the current application start timing using the current parameter map.

[0091] <<Interference reduction control processing flow>> FIG. 17 is a flowchart showing interference reduction control between the discharge amount control according to the learning state of the internal combustion engine 100 according to this embodiment and the first current application control (silencing control).

[0092] When a time interruption (typically 10 ms) occurs, the learning determination unit 1502 of the ECU 112 determines whether the internal combustion engine 100 is in the learning period based on the idle signal from the ECU 112, the rotation speed of the internal combustion engine 100, the load, etc. (step 1701). If the determination result in step 1401 is that the internal combustion engine 100 is in the learning period, the process proceeds to step 1702. If the determination result in step 1701 is that the internal combustion engine 100 is not in the learning period, the process proceeds to step 1703.

[0093] If the determination result in step 1701 is that the learning period is in progress, noise reduction control (first current application amount control) in first current application amount control unit 1201 shown in Fig. 9 is performed at 2 ms intervals (step 1702), and discharge amount control shown in Fig. 10 is performed at 10 ms intervals (step 1703). This processing flow is the same as in the first embodiment, so noise reduction control is performed based on the valve closure detection result, and the gain of the discharge amount control is suppressed when the valve is closed.

[0094] If the determination result in step 1701 is other than the learning period, discharge amount control is performed every 10 ms (step 1703). Meanwhile, valve closure determination unit 803 of ECU 112 performs valve closure determination (step 1704). Here, noise reduction control is not performed, and third current application amount control 1501 performs third current control based on current parameter memory 1503, and feedback control based on fuel pressure when plunger 202 rises is not performed.

[0095] During discharge amount control, the gain of the feedback control of the PON timing is changed based on whether the valve was successfully closed in the most recent valve closing judgment, as shown in Figure 10. This prevents excessive control by mistaking a drop in fuel pressure due to a valve closing failure for a drop in fuel pressure due to PON timing control.

[0096] <<Effects of this embodiment>> According to this embodiment, even if the valve fails to close due to a sudden change in fuel pressure or the like, it is possible to prevent excessive PON control from occurring due to fluctuations in fuel pressure caused by the valve failure to close.

[0097] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0098] 100...internal combustion engine, 101...fuel tank, 102...feed pump, 103...high-pressure fuel pump, 104...high-pressure piping, 105...direct injection injector, 106...cylinder, 107...piston, 108...spark plug, 109...link mechanism, 110...crankshaft, 111...low-pressure piping, 112...ECU, 200...electromagnetic actuator, 201...cam, 202...plunger, 203...intake valve, 204...anchor, 205...solenoid, 206...fixed portion, 207...seat portion, 208...stopper, 209...first spring, 210...discharge valve, 211...pressurizing chamber, 212...flow path, 215...second 2 spring, 221...communication port, 222...outlet, 223...casing, 225...inlet, 226...spring portion, 401...fuel pressure sensor, 402...plunger phase measurement portion, 403...discharge amount control portion, 801...plunger operation determination portion, 802...fuel pressure rise evaluation portion, 803...valve closing determination portion, 804...discharge amount control portion, 805...current application amount control portion, 1201...first current application amount control portion, 1202...second current application amount control portion, 1203...idle determination portion, 1204...current parameter memory, 1501...third current application amount control portion, 1502...learning period determination portion, 1503...current parameter memory.

Claims

1. A control device for controlling a high-pressure fuel pump, the control device being arranged between a low-pressure pipe and a high-pressure pipe to pressurize and discharge fuel from the low-pressure pipe into the high-pressure pipe, the control device including at least an intake valve arranged between the low-pressure pipe and a pressurizing chamber, a solenoid for controlling opening and closing of the intake valve, and a plunger for compressing fuel in the pressurizing chamber, A fuel pressure sensor is disposed in the high-pressure pipe, a plunger phase measurement unit that measures a phase angle of the plunger is provided near the plunger, a plunger operation determination unit that determines that the plunger is rising based on a phase angle of the plunger; a fuel pressure increase evaluation unit that evaluates an increase in fuel pressure during a period in which the plunger operation determination unit determines that the plunger is rising; a valve closing determination unit that determines whether the intake valve has been closed based on an evaluation result of the fuel pressure increase evaluation unit; a discharge amount control unit that controls the amount of fuel discharged by controlling a timing at which a current is applied to the solenoid based on the fuel pressure measured by the fuel pressure sensor and a target fuel pressure; Equipped with The discharge amount control unit determines a control gain for the timing to start applying current based on the determination result of the valve closing determination unit. High-pressure fuel pump control device.

2. 2. The high-pressure fuel pump control device according to claim 1, a current application amount control unit that controls the amount of current applied to the solenoid based on the determination result of the valve closing determination unit; High-pressure fuel pump control device.

3. 2. The high-pressure fuel pump control device according to claim 1, The discharge amount control unit reduces a control gain of a current application start timing when the determination result of the valve closing determination unit is a valve closing failure. High-pressure fuel pump control device.

4. 2. The high-pressure fuel pump control device according to claim 1, The discharge amount control unit controls the current application start timing based on a predetermined relationship between the fuel pressure and the current application start timing when the determination result of the valve closing determination unit is a valve closing failure. High-pressure fuel pump control device.

5. 3. The high-pressure fuel pump control device according to claim 2, The current application amount control unit controls the amount of current applied to the solenoid only when the operating state of the internal combustion engine is determined to be an idling state. High-pressure fuel pump control device.

Images