JP4220992B2 - 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 that controls the pressure of fuel injected from a fuel injection valve to a target pressure, and in particular, a novel control for a flow rate control valve for adjusting the fuel discharge amount of the high-pressure fuel pump. It is about technology.

In recent years, for the purpose of reducing exhaust gas, an engine of a system in which the fuel pressure is controlled to a desired high pressure value and the atomized fuel is injected has been put into practical use. In this type of engine, the fuel pressure is increased. A high-pressure fuel pump is provided.
The high-pressure fuel pump has a plunger that reciprocates in a pressurizing chamber, and the lower end of the plunger is in pressure contact with a pump cam provided on the cam shaft of the engine. When the pump cam rotates in conjunction with the rotation of the camshaft of the engine, the plunger reciprocates in the pressurizing chamber so that the volume in the pressurizing chamber changes.

The high-pressure passage (discharge passage) on the downstream side of the pressurization chamber is connected to the pressure accumulation chamber via a discharge valve (check valve) that allows only fuel to flow from the pressurization chamber to the pressure accumulation chamber. Is connected to a fuel injection valve for injecting fuel into each cylinder of the engine.
The low-pressure passage (supply passage) upstream of the pressurizing chamber is connected to the fuel tank via a normally open flow control valve, a low-pressure fuel pump and a low-pressure regulator, and is pumped from the low-pressure fuel pump to the low-pressure passage. After the fuel is adjusted to a predetermined feed pressure by the low pressure regulator, the flow rate is opened during the period when the plunger moves down from the top dead center to the bottom dead center (the period during which the volume of the pressurizing chamber expands) It is sucked into the pressurizing chamber through the control valve.

  Subsequently, the fuel sucked into the pressurizing chamber while the plunger is moving down is controlled at a predetermined timing during a period in which the plunger moves up from the bottom dead center to the top dead center (a period in which the volume of the pressurizing chamber decreases). By closing the valve, it is discharged into the stock pressure chamber as a desired fuel discharge amount pressurized.

Hereinafter, the relationship between the valve closing timing of the flow control valve and the fuel discharge amount during the plunger upward movement period will be described with reference to the drawings.
FIG. 12 is a timing chart showing a general fuel pressure control operation, and shows the relationship between the valve closing timing of the flow rate control valve and the fuel discharge amount (fuel discharge amount characteristic) during the plunger upward movement period.
In FIG. 12, in order from the top, the plunger operating position during the plunger upward movement period, the control state of the flow control valve (for example, when the flow control valve is controlled to close at time T12), and the flow control valve closed A fuel discharge amount Q corresponding to the valve timing is shown.

  In the fuel discharge amount Q in FIG. 12, the fuel amount QR that is not pressurized and is relieved to the low pressure passage (when the final drive timing TD = T12 of the flow control valve) is pressurized and discharged into the pressure accumulating chamber. Target fuel discharge amount QO (= QMAX−QR) (when TD = T12) and the fuel amount QMAX sucked into the pressurizing chamber during the downward movement of the plunger (maximum fuel discharge amount that can be discharged into the pressure accumulation chamber) Are equivalent to each other.

When the flow rate control valve is controlled to close at time T12 during the plunger upward movement period (the plunger operating position indicated by the solid line) in FIG. 12, the valve closing timing (time T12) from the plunger bottom dead center BDC (time T11). In the period up to, the flow rate control valve remains open.
Therefore, a part of the fuel amount QR of the fuel amount (= QMAX) sucked into the pressurizing chamber in the plunger lowering period immediately before the upward movement period is relieved to the low pressure passage through the opened flow control valve. .

  On the other hand, the flow rate control valve is closed during a period from time T12 when the flow rate control valve is energized and closed until the plunger top dead center TDC (time T13). In T12), the fuel amount (= QMAX-QR) remaining in the pressurizing chamber is pressurized and discharged into the accumulator chamber.

Further, when the valve closing timing is changed to the advance side (left side in FIG. 12) from time T12, the valve opening period is shortened and the valve closing period is lengthened, so that the fuel discharge amount Q is increased. Can do.
In the case of the fuel discharge amount characteristic shown in FIG. 12, the maximum amount of fuel discharge Q (= QMAX) is discharged into the animal pressure chamber when the time point of the plunger bottom dead center BDC (time T11) is the valve closing timing. The

On the contrary, when the valve closing timing is changed to the retard side (right side in FIG. 12) from time T12, the valve opening period becomes longer and the valve closing period becomes shorter, so the fuel discharge amount Q is decreased. be able to.
In the case of the fuel discharge amount characteristic shown in FIG. 12, the fuel discharge amount Q becomes the minimum amount (that is, zero) when the flow rate control valve is not closed at all during the plunger upward movement period.
Thus, by closing the flow control valve at a predetermined timing in the plunger upward movement period, the fuel discharge amount Q (target fuel discharge amount QO) discharged into the pressure accumulating chamber is changed from the maximum discharge amount QMAX to the minimum amount ( Can be adjusted to zero).

  The ECU constituting the control device determines a target pressure according to the engine operating state (for example, the engine speed and the amount of depression of the accelerator pedal), and calculates the fuel pressure in the pressure accumulating chamber detected by the fuel pressure sensor and the target pressure. Based on the pressure deviation, a proportional integral calculation or the like is executed to calculate the feedback amount of the valve closing timing.

  Further, the ECU calculates the feedforward amount at the valve closing timing based on the fuel injection amount injected from the fuel injection valve, adds the feedback amount at the valve closing timing and the feedforward amount, and calculates the fuel pressure in the pressure accumulating chamber. The target fuel discharge amount QO necessary for the engine to coincide with the target pressure is calculated, the valve closing timing for discharging the target fuel discharge amount QO is determined, and the flow control valve is controlled.

Various methods for controlling the valve closing timing of such a flow control valve have been conventionally proposed (see, for example, Patent Document 1 and Patent Document 2).
For example, in Patent Document 1, the valve closing timing is controlled by treating the valve closing period of the flow rate control valve in the plunger upward movement period as the duty ratio DT. That is, the duty ratio DT corresponds to the valve closing timing.

  In Patent Document 1, taking the case of FIG. 12 as an example, the valve closing timing (time T11) when controlling to the maximum fuel discharge amount QMAX is set to the duty ratio DT = 100%, and the minimum discharge amount (zero) is set. The valve closing timing at the time of control (time T13) is set to a duty ratio DT = 0%, and the valve closing period from time T12 to time T13 is obtained as the target duty ratio DT to control the valve closing timing.

Specifically, the valve closing timing at the time of maximum discharge (for example, 0 deg from the BDC of the pump cam) is set to DT = 100%, and the valve closing timing at the time of the minimum discharge amount (zero) (for example, after the BDC of the pump cam) 180 deg) is set to DT = 0%, and the target duty ratio DT is linearly controlled.
Assuming that the duty ratio DT with respect to the target fuel discharge amount QO is DT = 70%, 54 deg (= 180 deg− (70/100) × 180 deg) after BDC of the pump cam is determined as the valve closing timing.

In Patent Document 1, first, in order to determine the duty ratio DT corresponding to the valve closing timing, the basic duty ratio DB is determined from a map based on the engine speed and the target pressure.
The basic duty ratio DB is a correction value for absorbing the difference in fuel discharge amount efficiency that changes according to the engine speed and the target pressure.
Next, a pressure deviation ΔPF (= PO−PF) between the target pressure PO and the fuel pressure detection value (hereinafter simply referred to as “fuel pressure”) PF is calculated, and then the feedback proportional term DP (= ΔPF ×) of the duty ratio DT. KP (where KP is a positive proportional coefficient) and a feedback integral term DI (= DIn + KI × ΔPF, where DIn is the previous value and KI is a positive integral coefficient) of the duty ratio DT are calculated.
The feedback proportional term DP and the feedback integral term DI are correction values for obtaining the amount of fuel to be compensated in the stock pressure chamber in order to make the pressure deviation ΔPF zero.

Further, a feedforward term DF (= KF × QF, where KF is a positive coefficient and QF is a fuel injection amount) of the duty ratio DT is obtained. The feed forward term DF is a correction value for preventing the fuel pressure PF in the stock pressure chamber from being lowered by the fuel injection from the fuel injection valve.
Hereinafter, the ECU calculates a target fuel discharge amount QO necessary for the fuel pressure PF to coincide with the target pressure PO, calculates a duty ratio DT (= DB + DF + DP + DI) for discharging the target fuel discharge amount QO, and sets the flow rate. Drive the control valve.

Here, for example, when the fuel pressure PF is lower than the target pressure PO (when the pressure deviation ΔPF = PO−PF> 0), the feedback proportional term DP becomes a positive value proportional to the pressure deviation ΔPF, and the feedback integral The term DI increases by a positive value according to the pressure deviation ΔPF.
As a result, the duty ratio DT increases (the valve closing timing moves to the advance side) and the fuel discharge amount Q increases, so that the fuel pressure PF can be raised toward the target pressure PO.

On the other hand, when the fuel pressure PF is higher than the target pressure PO (when the pressure deviation ΔPF = PO−PF <0), the feedback proportional term DP becomes a negative value proportional to the pressure deviation ΔPF, and the feedback integral term DI is , It decreases by a negative value according to the pressure deviation ΔPF.
As a result, the duty ratio DT decreases (the valve closing timing moves to the retard side) and the fuel discharge amount Q decreases, so that the fuel pressure PF can be lowered toward the target pressure PO.

In Patent Document 2, the valve closing angle position of the flow control valve is directly determined without using the duty ratio DT. If this point is excluded, also in patent document 2, the valve closing timing of a flow control valve will be determined by the same calculation method as patent document 1.
That is, in both Patent Document 1 and Patent Document 2, basically, the feedback amount of the valve closing timing of the flow control valve is calculated based on the pressure deviation ΔPF between the target pressure PO and the fuel pressure PF, and the fuel injection amount is calculated. Based on the above, the feedforward amount of the closing timing of the flow control valve is calculated, the feedback amount of the closing timing and the feedforward amount are added, and the closing timing itself of the flow control valve is determined. A control method for driving is adopted.

Next, an actual control operation in Patent Document 1 will be described with reference to FIGS. 13 and 14.
FIG. 13 is a timing chart showing the control operation when the target pressure PO changes suddenly stepwise.
FIG. 14 is an explanatory diagram showing the relationship (fuel discharge amount characteristic) between the duty ratio DT and the fuel discharge amount Q, and the operating point A1 on the fuel discharge amount characteristic when the target pressure PO changes suddenly stepwise. , A2.

In FIG. 13, in order from the top, the fuel pressure PF and the target pressure PO (one-dot chain line), the feedback proportional term DP of the duty ratio DT, the feedback integral term DI of the duty ratio DT, and the feedforward term DF of the duty ratio DT. And the behavior of the duty ratio DT are shown in association with each other.
In this case, in the initial state before time T21, the fuel injection amount QF = qf1 and the duty ratio DT = dt1, and the target pressure PO and the fuel pressure PF coincide with each other. An example of the operation when only the pressure increase amount pf1 is suddenly changed to the high pressure side is shown.

  It is assumed that the fuel injection amount QF (= qf1) does not change before and after time T21 when the target pressure PO changes suddenly, and the basic duty that is originally required to absorb the difference in efficiency of the fuel discharge amount Q. The description will proceed assuming that the ratio DB is zero.

In the initial state in FIG. 13, since the target pressure PO and the fuel pressure PF coincide with each other, the feedback proportional term DP shows almost zero, and if there is no variation in the fuel supply system, feedback is performed. The integral term DI is also almost zero, and each controlled variable is in a stationary state.
Further, since the fuel injection amount QF = qf1 (constant), the feedforward term DF (= QF × KF = qf1 × KF) is also a constant calculation value.
At this time, since the valve closing timing is controlled by the duty ratio DT (= DB + DP + DI + DF = 0 + 0 + 0 + qf1 × KF = dt1) and the initial state is maintained, the operating point is the position A1 (duty ratio DT = dt1, fuel discharge amount Q = qf1).

  After that, at time T21 in FIG. 13, when the target pressure PO suddenly changes to the high pressure side by the pressure increase amount pf1, a positive pressure deviation ΔPF = PO−PF = pf1 occurs, and the feedback proportional term DP (= pf1 × KP) Is calculated and added to the duty ratio DT, so that the duty ratio DT changes stepwise from DT = dt1 to DT = dt2 (= dt1 + pf1 × KP).

The operating point at this time changes stepwise from position A1 in FIG. 14 to position A2.
That is, when the duty ratio DT changes from DT = dt1 to DT = dt2, the fuel discharge amount Q is increased from Q = qf1 to Q = qf1 + qp1.
The increase qp1 of the fuel discharge amount Q is a fuel amount to be compensated in the animal pressure chamber in order to make the pressure deviation ΔPF (= pf1) generated when the target pressure PO suddenly changes to the high pressure side by the increase amount pf1. This corresponds to the initial value and acts to raise the fuel pressure PF toward the target pressure PO.

Therefore, after time 21 in FIG. 13, the pressure deviation ΔPF decreases from the pressure increase amount pf1 in accordance with the increase qp1 of the fuel discharge amount Q, and accordingly, the feedback proportional term DP is changed from pf1 × KP. At time T22 when the pressure deviation ΔPF decreases to zero and returns to DP = 0.
Thus, at time T21, the duty ratio DT that changes stepwise from DT = dt2 to DT = dt2 becomes smaller in conjunction with the reduction of the pressure deviation ΔPF during the period after time T21.

On the other hand, the feedback integral term DI also increases somewhat due to the generated positive pressure deviation ΔPF during the period from time T21 when the target pressure PO changes stepwise to time T22 when the pressure deviation ΔPF returns to zero.
Therefore, after time T22 when the pressure deviation ΔPF returns to zero, the fuel pressure PF shows a behavior with some overshoot due to the excessively increased feedback integral term DI, and then converges toward the target pressure PO. (See FIG. 13).

  After the time T23 when the fuel pressure PF has completely converged to the target pressure PO, the valve closing timing is controlled with the duty ratio DT (= dt1) and the target pressure PO and the fuel pressure PF are again set as in the initial state. The feedback proportional term DP and the feedback integral term DI return to a stationary state with a substantially zero control amount.

Next, the problem in the prior art disclosed in Patent Document 1 will be described with reference to the timing chart of FIG. 15 and the explanatory diagram of FIG.
FIG. 15 shows the fuel pressure PF and the target pressure PO, the feedback proportional term DP of the duty ratio DT, the feedback integral term DI of the duty ratio DT, and the feedforward term DF of the duty ratio DT in order from the top as in FIG. The behavior of the duty ratio DT is shown in association with each other.

In this case, in the initial state before time T31, the fuel injection amount QF = qf2 (> qf1) and the duty ratio DT = dt3 are set, and the target pressure PO and the fuel pressure PF coincide with each other at the time T31. An operation example when only the pressure PO is suddenly changed to the high pressure side by the pressure increase amount pf1 is shown.
It is assumed that the fuel injection amount QF (= qf2) does not change before and after the time T31 when the target pressure PO changes suddenly, and the basic duty that is originally required to absorb the difference in efficiency of the fuel discharge amount Q. The description will proceed assuming that the ratio DB is zero.
FIG. 16 shows the relationship between the duty ratio DT and the fuel discharge amount Q (fuel discharge amount characteristics), as well as FIG. 14, and also shows the operating points A3 to A5 in the operating state of FIG.

In the initial state in FIG. 15, the feedback proportional term DP is almost zero because the target pressure PO and the fuel pressure PF coincide with each other, and the feedback integral term DI is also almost zero when there is no variation in the fuel supply system. Each control amount is in a stationary state.
Further, since the fuel injection amount QF = qf2 (constant), the calculated value of the feedforward term DF (= QF × KF = qf2 × KF) is also a constant value.
At this time, since the valve closing timing is controlled by the duty ratio DT (= DB + DP + DI + DF = 0 + 0 + 0 + qf2 × KF = dt3) and the initial state is maintained, the operating point is the position A3 (duty ratio DT = dt3 in FIG. 16). The fuel discharge amount Q = qf2).

  Thereafter, at time T31 in FIG. 15, when the target pressure PO suddenly changes to the high pressure side by the same pressure increase amount pf1 as described above, a positive pressure deviation ΔPF (= PO−PF = pf1) is generated, and the feedback proportional term DP ( = Pf1 * KP) is calculated and added to the duty ratio DT, so that the duty ratio DT changes stepwise from DT = dt3 to DT = dt4 (= dt3 + pf1 * KP).

The operating point at this time changes stepwise from position A3 in FIG. 16 to position A4.
However, since the operating point A4 is located outside the linear region (QLL <Q <QHH) in which the relationship between the duty ratio DT and the fuel discharge amount Q is substantially linear, the pressure is similar to that described above (see FIG. 14). Even if the duty ratio DT increases by the feedback proportional term DP (= pf1 × KP) proportional to the deviation ΔPF (= pf1), there occurs a situation where the fuel discharge amount Q can be increased only by the increase qp2 (<qp1). .

  That is, in order to obtain the increase qp1 (see FIG. 14) of the required fuel discharge amount Q, it is necessary to set the duty ratio DT to DT = dt5 (> dt4) as shown in FIG. Regardless, since the influence of the non-linear region of the fuel discharge amount characteristic (see FIG. 16) is not considered in the conventional calculation method, the change in the duty ratio DT is an insufficient value from DT = dt3 to DT = dt4. Will stay.

As a result, although the duty ratio DT is changed by the same pf1 × KP as described above (FIG. 14), the increase amount of the fuel discharge amount Q with respect to the change amount of the duty ratio DT is the increase qp1 described above (FIG. 14). The increase qp2 is smaller than that.
Therefore, the amount of increase in the fuel discharge amount Q required to increase the fuel pressure PF decreases, and the response time required from the time T31 when the target pressure PO changes stepwise until the fuel pressure PF matches the target pressure PO. It will be much longer.

Further, as shown in FIG. 15, the time required for the fuel pressure PF to coincide with the target pressure PO is longer than that in the case of FIG. 13, so that the pressure deviation from the time T31 when the target pressure PO changes stepwise. The feedback integral term DI increases to an excessive value due to the generated positive pressure deviation ΔPF until time T32 when ΔPF returns to zero.
As a result, the fuel pressure PF exhibits a behavior with a large overshoot due to the excessively increased feedback integral term DI at time T32 when the pressure deviation ΔPF returns to zero, and thereafter, the time T33 when the feedback integral term DI becomes zero. The state where the fuel pressure PF exceeds the target pressure PO continues for a long period of time.

Japanese Patent Laid-Open No. 5-288098 JP 11-324757 A

  As described above, the conventional high-pressure fuel pump control device of the engine has the fuel discharge amount characteristic when the operating point A4 is out of the linear region (the fuel discharge amount Q is outside the range of QLL <Q <QHH). Since the period in which the fuel pressure PF and the target pressure PO do not coincide with each other is significantly long, optimal combustion performance is obtained for the engine operating state, and this causes problems such as drivability and exhaust gas deterioration. was there.

  The present invention has been made in order to solve the above-described problem. By determining the valve closing timing so that the fuel discharge amount is properly discharged regardless of the use region of the fuel discharge amount characteristic, the fuel pressure is determined. To obtain a high-pressure fuel pump control device for an engine that avoids the problem that the optimal combustion performance cannot be obtained and the driving performance deteriorates due to the deterioration of the period during which the target pressure does not match the target pressure. Objective.

The high-pressure fuel pump control apparatus for an engine according to the present invention includes various sensors that detect the operating state of the engine, a fuel injection valve that supplies fuel to each combustion chamber of the engine, and a high-pressure that supplies pressurized fuel to the fuel injection valve. A fuel pump, a flow rate control valve for adjusting the fuel discharge amount of the high pressure fuel pump, target pressure determining means for determining a target pressure according to the operating state of the engine, and the high pressure fuel pump are supplied to the fuel injection valve A fuel pressure sensor that detects the pressure of the fuel and outputs a fuel pressure detection value; a pressure deviation calculation means that calculates a pressure deviation between the target pressure and the fuel pressure detection value; and the pressure deviation by multiplying the pressure deviation by a proportional coefficient. Pressure deviation compensation flow rate calculation means for calculating the pressure deviation compensation flow rate required to make zero, and fuel injection amount for calculating the fuel injection amount from the fuel injection valve according to the operating state of the engine A calculation means, a target fuel discharge amount determining means for determining a target fuel discharge amount of the high-pressure fuel pump by adding the pressure deviation compensation flow rate and the fuel injection amount, and a target fuel discharge amount and a drive timing of the flow control valve. Map storage means for storing fuel discharge amount characteristics indicating the relationship in advance, reference drive timing determination means for determining the reference drive timing of the flow control valve corresponding to the target fuel discharge amount using the fuel discharge amount characteristics, and pressure deviation Drive timing correction means for calculating the feedback integral correction value of the reference drive timing by performing integration processing according to the direction of the sign of the reference, and flow control at the final drive timing after the reference drive timing is corrected by the feedback integral correction value And a flow control valve driving means for driving the valve.

According to this invention, the pressure deviation compensation flow rate required to make the pressure deviation between the target pressure and the fuel pressure zero is obtained, and from the target fuel discharge amount obtained by adding the pressure deviation compensation flow rate and the fuel injection amount, The reference drive timing is determined based on the fuel discharge amount characteristic, the reference drive timing is corrected using the feedback integral correction value that is integrated according to the sign direction of the pressure deviation, and the final valve closing timing is determined. This makes it possible to control the appropriate fuel discharge amount over the entire area of the fuel discharge amount characteristic, shorten the period when the fuel pressure does not match the target pressure, and obtain the optimal engine combustion performance. Improvements can be realized.

Embodiment 1 FIG.
Hereinafter, an engine high-pressure fuel pump control apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing Embodiment 1 of the present invention, and mainly shows the configuration of a fuel supply system.

  In FIG. 1, the fuel supply system is connected to a high-pressure fuel pump 20 that is operated by a pump cam 25 integrated with a camshaft 24, a fuel tank 30 that is filled with fuel supplied to the high-pressure fuel pump 20, and the fuel tank 30. Low pressure fuel pump 31 and low pressure regulator 32, low pressure passage (supply passage) 33 connected to low pressure fuel pump 31 and low pressure regulator 32, high pressure passage (discharge passage) 34 connected to high pressure fuel pump 20, and high pressure passage 34, a pressure accumulation chamber 36 that stores fuel discharged from the high-pressure fuel pump 20, and a relief passage 38 that connects the pressure accumulation chamber 36 and the fuel tank 30 via a relief valve 37. Yes.

A high-pressure fuel pump 20 for pressurizing fuel to a high pressure includes a normally-open flow control valve 10 comprising an electromagnetic solenoid 11, a spring 12, a fuel inlet 13 and a valve body 14, and a cylinder connected to the flow control valve 10. 21, a plunger 22 that reciprocates in the cylinder 21, and a pressurizing chamber 23 for pressurizing fuel during the upward movement of the plunger 22.
The lower end of the plunger 22 is pressed against a pump cam 25 provided on the cam shaft 24 of the engine 40, and the pump cam 25 rotates in conjunction with the rotation of the cam shaft 24, so that the plunger 22 reciprocates in the cylinder 21. The volume in the pressurizing chamber 23 is changed in an enlarged / reduced manner.

A fuel injection valve 39 of the engine 40 is connected to the pressure accumulation chamber 36.
The electromagnetic solenoid 11 and the fuel injection valve 39 are controlled by an ECU (electronic control unit) 60 having a microcomputer.
That is, the fuel injection valve 39 is controlled to be opened and closed under the control of the ECU 60, and determines the fuel injection amount and the injection timing to the engine 40.

Further, the electromagnetic solenoid 11 of the flow control valve 10 in the high-pressure fuel pump 20 is energized under the control of the ECU 60, thereby closing the valve as described later, and determining the fuel discharge amount Q to the pressure accumulating chamber 36. To do.
On the other hand, in a state where the energization to the electromagnetic solenoid 11 is stopped, the flow control valve 10 is opened by the urging force of the spring 12.

A fuel pressure sensor 61 that detects the fuel pressure PF in the pressure accumulation chamber 36 is provided in the pressure accumulation chamber 36.
Further, as various sensors for detecting the operating state of the engine 40, a crank angle sensor 62 for detecting the rotational speed NE of the engine 40, an accelerator position sensor 63 for detecting a depression amount AP of an accelerator pedal (not shown), an engine There is provided idle detection means 64 for detecting an idle operation state of 40 and generating an idle determination flag Fi. Illustrations of other known sensors are omitted.
Operating conditions such as the engine speed NE, the accelerator depression amount AP, and the idle determination flag Fi are input to the ECU 60 together with the fuel pressure PF, and are used to calculate control amounts for the fuel injection valve 39 and the electromagnetic solenoid 11.

In the fuel supply system in FIG. 1, the low pressure passage 33 connected upstream of the pressurizing chamber 23 is connected to the fuel tank 30 via the low pressure fuel pump 31.
The low pressure fuel pump 31 pumps up the fuel in the fuel tank 30 and discharges it to the low pressure passage 33. The fuel discharged from the low pressure fuel pump 31 is adjusted to a predetermined feed pressure by the low pressure regulator 32.
The fuel in the low pressure passage 33 is introduced into the pressurizing chamber 23 through the fuel suction port 13 in the flow control valve 10 when the plunger 22 in the high pressure fuel pump 20 moves down in the cylinder 21.

On the other hand, the high-pressure passage 34 connected downstream of the pressurizing chamber 23 is connected to the pressure accumulating chamber 36 via the discharge valve 35.
The discharge valve 35 functions as a check valve that allows only fuel to flow from the pressurizing chamber 23 toward the pressure accumulating chamber 36.
The pressure accumulating chamber 36 accumulates and holds the high-pressure fuel discharged from the pressurizing chamber 23, and is connected in common to each fuel injection valve 39 to distribute the high-pressure fuel to the fuel injection valve 39.

The relief valve 37 connected to the pressure accumulating chamber 36 is a normally closed valve that opens at a predetermined valve opening pressure set value or higher, and the fuel pressure in the pressure accumulating chamber 36 is equal to or higher than the valve opening pressure set value of the relief valve 37. Opens when trying to rise.
As a result, the fuel in the pressure accumulating chamber 36 that is about to rise above the valve opening pressure setting value is returned to the fuel tank 30 through the relief passage 38, so that the fuel pressure in the pressure accumulating chamber 36 does not become excessive.

The flow rate control valve 10 constituted by a normally open solenoid valve opens the fuel suction port 13 so that the low pressure passage 33 and the pressurizing chamber 23 communicate with each other when the electromagnetic solenoid 11 is not energized. It becomes a state.
When the plunger 22 moves in the direction in which the volume of the pressurizing chamber 23 increases (downward in FIG. 1) when the flow control valve 10 is opened (during the intake stroke of the high-pressure fuel pump 20), the low-pressure fuel pump 31. The fuel delivered from is sucked into the pressurizing chamber 23 through the low-pressure passage 33.

On the other hand, when the plunger 22 moves in the direction in which the volume of the pressurizing chamber 23 contracts (upward in FIG. 1) (during the pumping stroke of the high-pressure fuel pump 20), the flow rate is increased when the electromagnetic solenoid 11 is energized. The electromagnetic solenoid 11 of the control valve 10 is closed against the spring 12.
As a result, the fuel suction port 13 is closed and the communication between the low pressure passage 33 and the pressurizing chamber 23 is blocked. Therefore, as the plunger 22 moves, the fuel pressure in the pressurizing chamber 23 rises and discharges. By opening the valve 35, pressurized fuel is supplied to the pressure accumulating chamber 36.

The adjustment of the fuel discharge amount Q from the high-pressure fuel pump 20 is performed by operating the valve closing start timing of the flow control valve 10 during the pressure feed stroke.
That is, if the valve closing start timing of the flow control valve 10 is advanced to the advance side and the valve closing period is set longer, the fuel discharge amount increases, and conversely, the valve closing start timing of the flow control valve 10 is retarded. However, if the valve closing period is set short, the fuel discharge amount decreases.
Thus, the fuel pressure PF in the pressure accumulating chamber 36 is controlled by adjusting the fuel discharge amount Q of the high-pressure fuel pump 20.

  The ECU 60 determines the fuel pressure PF in the pressure accumulating chamber 36 detected by the fuel pressure sensor 61, the engine rotational speed NE detected by the crank angle sensor 62, and the accelerator depression amount AP detected by the accelerator position sensor 63. Information is taken in to determine the target pressure PO, and the closing timing of the flow control valve 10 is determined so that the target pressure PO and the fuel pressure PF in the pressure accumulating chamber 36 coincide with each other. Control the quantity Q.

Next, a specific control function of the ECU 60 in FIG. 1 will be described with reference to FIG.
FIG. 2 is a functional block showing the control function configuration of the ECU 60. The same components as those described above (FIG. 1) are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.
In FIG. 2, the aforementioned flow control valve 10, fuel pressure sensor 61, crank angle sensor 62, accelerator position sensor 63, and idle detection means 64 are connected to the outside of the ECU 60.

  The ECU 60 includes a target pressure determining unit 601 that determines the target pressure PO, a pressure deviation calculating unit 602 that includes a subtractor 602a that calculates the pressure deviation ΔPF, and a pressure deviation compensating flow rate calculating unit 603 that calculates a pressure deviation compensating flow rate QP. The fuel injection amount calculating means 604 for calculating the fuel injection amount QF, the target fuel discharge amount determining means 605 for determining the target fuel discharge amount QO, the reference drive timing determining means 606 for determining the reference drive timing TB, and the reference drive A drive timing correction unit 607 that calculates a correction value TI for the timing TB, an adder 608 that determines the final drive timing TD, a flow rate control valve drive unit 609 that drives the flow rate control valve 10, and a change amount ΔPF of the pressure deviation ΔPF. Change amount calculation means 610 for calculating / dt, and a flow rate for determining a flow rate decrease state of the fuel discharge amount Q It includes a lower judging means 611.

In the ECU 60, the target pressure determining means 601 determines the target pressure PO by performing a map search based on the engine speed NE and the accelerator depression amount AP from the sensors 62 and 63.
The subtractor 602a constituting the pressure deviation calculating means 602 calculates a pressure deviation ΔPF (= PO−PF) between the target pressure PO determined by the target pressure determining means 601 and the fuel pressure PF detected by the fuel pressure sensor 61. .

The pressure deviation compensation flow rate calculation means 603 calculates a pressure deviation compensation flow rate QP (= ΔPF × KP) necessary for making the pressure deviation ΔPF zero by multiplying the pressure deviation ΔPF by the proportional coefficient KP. Note that the proportionality coefficient KP is set in advance using an experimental method or the like.
The fuel injection amount calculation means 604 calculates a fuel injection amount QF to be injected from the fuel injection valve 39 in accordance with the operating state of the engine 40 (see FIG. 1).
The target fuel discharge amount determination unit 605 adds the pressure deviation compensation flow rate QP calculated by the pressure deviation compensation flow rate calculation unit 603 and the fuel injection amount QF calculated by the fuel injection amount calculation unit 604 to add the target fuel discharge amount. Determine the quantity QO.

The reference drive timing determining means 606 has map storage means for storing in advance, as map data, a fuel discharge amount characteristic indicating the relationship between the target fuel discharge amount QO of the high-pressure fuel pump 20 and the drive timing of the flow control valve 10. Yes.
The reference drive timing determination unit 606 converts the target fuel discharge amount QO determined by the target fuel discharge amount determination unit 605 into the reference drive timing TB of the flow control valve 10 using the fuel discharge amount characteristic data stored in advance. To do.

  If the fuel discharge amount characteristic varies depending on values such as the engine speed NE and the target pressure PO, for example, a plurality of fuel discharge amount characteristic data is prepared for each engine speed NE and the target pressure PO in advance. In addition, appropriate fuel discharge amount characteristic data is selected and used in accordance with the engine speed NE and the target pressure PO when actually used. Thereby, the difference in fuel discharge efficiency which changes for every engine speed NE and target pressure PO can be corrected.

The drive timing correction means 607 calculates the correction value TI of the reference drive timing TB as, for example, TI = TIn + KI or TI = TIn−KI, according to the sign direction (positive / negative) of the pressure deviation ΔPF. However, the correction value TI is a value having both positive and negative signs, TIn is a previous value, and KI is an integration coefficient.
The adder 608 adds the reference drive timing TB and the correction value TI to determine the final drive timing TD (= TB + TI).
The flow control valve drive means 609 controls energization of the electromagnetic solenoid 11 (see FIG. 1) in the flow control valve 10 so that the flow control valve 10 is closed at the final drive timing TD.

The change amount calculation means 610 calculates the change amount ΔPF / dt of the pressure deviation ΔPF determined by the pressure deviation calculation means 602 and inputs it to the ECU 60.
Further, the idle detection means 64 inputs an idle determination flag Fi (“1” is set when the engine 40 is idle) to the ECU 60.

  The drive timing correction means 607 is such that the target fuel discharge amount QO determined by the target fuel discharge amount determination means 605 is a value within the linear characteristic range of the fuel discharge amount characteristic data (QLL <QO <QHH in FIG. 5 described later). Is updated, the correction value TI of the reference drive timing TB is updated. When the target fuel discharge amount QO indicates a value outside the linear characteristic range, the update of the correction value TI of the reference drive timing TB is interrupted. It is supposed to be.

  In addition, when the idle determination flag Fi indicates the idle operation state (Fi = 1) of the engine 40, the drive timing correction unit 607 updates the correction value TI of the reference drive timing TB and does not perform the idle operation ( If Fi = 0), the update of the correction value TI of the reference drive timing TB is interrupted.

  Further, the drive timing correction means 607 is when the change amount ΔPF / dt calculated by the change amount calculation means 610 is small and indicates a predetermined change amount KD or less (when the fuel pressure PF with respect to the target pressure PO is not in a transient state). When the correction value TI of the reference drive timing TB is updated and the change amount ΔPF / dt is large and exceeds the predetermined change amount KD (when the fuel pressure PF with respect to the target pressure PO indicates a transient state), the reference drive is performed. Update of the correction value TI of the timing TB is interrupted.

  Based on the target fuel discharge amount QO determined by the target fuel discharge amount determination unit 605 and the correction value TI from the drive timing correction unit 607, the flow rate decrease determination unit 611 is provided with a low flow rate region correction value TIL and a high flow rate region. When the correction value TIH is obtained and the high flow rate region correction value TIH indicates an advance side value than the low flow rate region correction value TIL, the fuel discharge amount Q with respect to the drive timing of the flow rate control valve 10 decreases. The determination result is input to the reference drive timing determination means 606.

That is, the flow rate decrease determination unit 611 uses the correction value TI when the target fuel discharge amount QO is in a predetermined low flow rate range (in the range of QLL <QO <QLH in FIG. 10 described later) as the low flow rate correction value TIL. And the correction value TI when the target fuel discharge amount QO is within a predetermined high flow rate range (in the range of QHL <QO <QHH in FIG. 10 described later) is stored as the high flow rate range correction value TIH. When the flow rate region correction value TIH is higher than the flow rate region correction value TIL, it is determined that the flow rate is in a lowered state.
When storing the low flow rate region correction value TIL and the high flow rate region correction value TIH, for example, a value obtained by reading the correction value TI in each flow region a plurality of times and averaging may be used.

  The reference drive timing determination unit 606, when the flow rate decrease determination unit 611 determines that the flow rate has decreased, sets the target fuel discharge amount QO value (stored in advance) with respect to the drive timing of the flow rate control valve 10 as the current value. The fuel discharge amount characteristic data is updated by changing to a value smaller than the value.

Next, a specific control operation of ECU 60 according to the first embodiment of the present invention will be described with reference to the flowchart of FIG.
In FIG. 3, first, the ECU 60 reads the engine speed NE, the accelerator depression amount AP, the fuel pressure PF, and the fuel injection amount QF (step S101), and the target pressure determining means 601 reads the engine rotation speed NE and the accelerator pedal depression amount. The target pressure PO is determined by map search based on AP (step S102).

Subsequently, the pressure deviation calculating means 602 calculates a pressure deviation ΔPF (= PO−PF) between the target pressure PO and the fuel pressure PF (step S103), and the pressure deviation compensating flow rate calculating means 603 is proportional to the pressure deviation ΔPF. The pressure deviation compensation flow rate QP (= ΔPF × KP) necessary for making the pressure deviation ΔPF zero is calculated by multiplying KP (step S104).
Further, the target fuel discharge amount determination means 605 adds the pressure deviation compensation flow rate QP and the fuel injection amount QF to determine the target fuel discharge amount QO (= QP + QP) (step S105).

  Subsequently, the reference drive timing determination unit 606 uses the fuel discharge amount characteristic data indicating the relationship between the target fuel discharge amount QO of the high-pressure fuel pump 20 and the drive timing of the flow control valve 10 to flow the target fuel discharge amount QO. The control valve 10 is converted into a reference drive timing TB, and the reference drive timing TB is input to the adder 608 (step S106).

  In the case where a plurality of fuel discharge amount characteristic data are prepared for each engine speed NE and target pressure PO in the reference drive timing determination means 606 in consideration of the fuel discharge efficiency as described above. Appropriate fuel discharge amount characteristic data is selected and used according to the engine speed NE read in step S101 and the target pressure PO determined in step S102.

Next, the drive timing correction unit 607 sets the update permission flag F to “1” in order to determine whether or not the update of the correction value TI is permitted with respect to the reference drive timing TB determined in step S106. It is determined whether or not (step S107).
If it is determined in step S107 that F = 0 (that is, NO), the process proceeds to step S112 described later.
On the other hand, if it is determined in step S107 that F = 1 (that is, YES), then the direction of the sign of the pressure deviation ΔPF (ΔPF <0, ΔPF = 0, or ΔPF> 0) is determined (step). S108).

If it is determined in step S108 that the sign of the pressure deviation ΔPF is negative (ΔPF <0), the correction value TI of the reference drive timing TB is reduced by a predetermined value KI, and TI = TIn−KI is calculated (step S109). The process proceeds to step S112.
If it is determined in step S108 that the sign of the pressure deviation ΔPF is neither positive nor negative (ΔPF = 0), the current value TI is held without updating the correction value TI of the reference drive timing TB ( The process proceeds to step S110) and step S112.

Further, if it is determined in step S108 that the sign of the pressure deviation ΔPF is positive (ΔPF> 0), the correction value TI of the reference drive timing TB is increased by a predetermined value KI, and TI = TIn + KI is calculated (step S111). Proceed to step S112.
Note that if the process is always performed with “F = 1” (update permission state), the process proceeds from step S107 to step S108.

Next, in steps S112 and S113, processing for limiting the correction value TI of the reference drive timing TB to a predetermined range set in advance is executed.
At this time, the predetermined range corresponding to the correctable range of the reference drive timing TB is set as a value within the variation range of the maximum timing assumed at the normal time.

Following steps S107 to S111, first, the correction value TI of the reference drive timing TB is limited to the maximum value TIMEMAX (step S112).
As a result, the correction value TI of the reference drive timing TB is prevented from being corrected to increase to the plus side (retard side) with respect to the maximum value TIMAX.
Further, the correction value TI of the reference drive timing TB is limited to the minimum value TIMIN (step S113).
As a result, the correction value TI of the reference drive timing TB is avoided from being corrected to decrease to the minus side (advance side) from the minimum value TIMIN.

Subsequently, the final drive timing TD (= TB + TI) is calculated by adding the reference drive timing TB determined in Step S106 and the correction value TI of the reference drive timing TB limited in Steps S112 and S113 (Step S106). S114).
Finally, the flow control valve 10 is driven and controlled at the final drive timing TD calculated in step S114 (step S115), and the processing routine of FIG.

Next, after applying the valve closing timing control method of the flow control valve 10 according to the first embodiment of the present invention, referring to FIGS. 4 and 5 similar to the above (FIGS. 15 and 16), the target A control operation when the pressure PO changes stepwise will be described.
FIG. 4 is a timing chart showing the control operation according to the first embodiment when the target pressure PO changes suddenly. From the top, the fuel pressure PF, the target pressure PO (one-dot chain line), the pressure deviation compensation flow rate QP, and the fuel The injection amount QF, the target fuel discharge amount QO, the correction value TI of the reference drive timing TD, and the final valve closing timing TD are shown.

In FIG. 4, similarly to the above (FIG. 15), the initial state (before time T41) in which the target pressure PO and the fuel pressure PF coincide with each other at the fuel injection amount QF = qf2 and the final drive timing TD = dt3. The operation example when only the target pressure PO is suddenly changed to the high pressure side by the pressure increase amount pf1 at time T41 from the state) is shown.
The description will be made assuming that the fuel injection amount QF = qf2 does not change before and after the target pressure PO changes stepwise.

FIG. 5 is an explanatory diagram showing a relationship (fuel discharge amount characteristic) between the final drive timing TD of the flow control valve 10 and the target fuel discharge amount QO, and operating points A3 and A5 in the operation state of FIG. 4 are added. ing.
Note that the map data in FIG. 5 indicates which drive timing should be determined when it is desired to discharge the fuel of the target fuel discharge amount QO, and the horizontal axis indicates the duty ratio corresponding to the valve closing timing (angle). DT is shown.

  That is, in the present invention, when the closing timing of the flow rate control valve 10 is controlled, the relationship between the duty ratio DT (valve closing timing) on the horizontal axis and the target fuel discharge amount QO of the high-pressure fuel pump 20 on the vertical axis. Is used to determine the valve closing timing (= drive angle) for achieving the target fuel discharge amount QO.

  In the initial state in FIG. 4 (the state before time T41), the target pressure PO and the fuel pressure PF coincide with each other as described above. Therefore, the pressure deviation compensation flow rate QP shows almost zero, and the fuel injection amount Since QF = qf2 is constant, the target fuel discharge amount QO (= QP + QF = qf2) is a constant calculation value.

Further, when there is no variation in the fuel supply system, the correction value TI of the reference drive timing TB is almost zero and is in a stationary state.
Therefore, the final valve closing timing TD and the target fuel discharge amount QO determined using the fuel discharge amount characteristic (see FIG. 5) based on the target fuel discharge amount QO (= qf2) are closed at the duty ratio DT = dt3. Since the timing is controlled and the initial state is maintained, the operating point A3 in FIG. 5 (final valve closing timing TD corresponding to DT = dt3, target fuel discharge amount QO = qf2) is obtained.

Thereafter, at time T41 in FIG. 4, when the target pressure PO suddenly changes to the high pressure side by the pressure increase amount pf1, a positive pressure deviation ΔPF (= PO−PF = pf1) is generated, and the pressure deviation compensation flow rate QP (= pf1). XKP) is calculated and added to the target fuel discharge amount QO, whereby the target fuel discharge amount QO increases to QO = qf2 + qp1.
Further, the final valve closing timing TD determined using the fuel discharge amount characteristic (FIG. 5) changes stepwise from the corresponding value of the duty ratio DT = dt3 to the corresponding value of DT = dt5.
At this time, the operating point changes stepwise from position A3 in FIG. 5 to position A5.

That is, as the final drive timing TD changes from TD = dt3 to TD = dt5, the target fuel discharge amount QO discharged from the high-pressure fuel pump is immediately increased from QO = qf2 to QO = qf2 + qp1.
The increased target fuel discharge amount QO (= qf2 + qp1) acts to quickly increase the fuel pressure PF by the increased pressure amount pf1, as described above (FIG. 13).

Therefore, after time 41 in FIG. 4, as in the above (FIG. 13), the pressure deviation ΔPF becomes smaller than the pressure increase amount pf1 in accordance with the increase in the target fuel discharge amount QO. The deviation compensation flow rate QP is also smaller than the increase qp1, and at time T42 when the pressure deviation ΔPF returns to zero, the pressure deviation compensation flow rate QP returns to QP = 0.
During this period, the final drive timing TD that changes stepwise to the corresponding value of the duty ratio DT = dt5 also becomes smaller in conjunction with the reduction of the pressure deviation ΔPF.

On the other hand, the correction value TI of the reference drive timing TB is somewhat increased by the generated positive pressure deviation ΔPF from time T41 when the target pressure PO changes stepwise to time T42 when the pressure deviation ΔPF returns to zero. However, it falls within the same range as described above (FIG. 13).
Therefore, the fuel pressure PF in FIG. 4 shows a behavior with a slight overshoot due to the reference value correction timing TI that has increased excessively at the time T42 when the pressure deviation ΔPF returns to zero, but the target pressure Converge toward PO.

After the time T43 when the fuel pressure PF has completely converged to the target pressure PO, the target pressure PO and the fuel pressure PF are controlled while the valve closing timing is controlled at the final drive timing TD (corresponding value of DT = dt3) as in the initial state. And the pressure deviation compensation flow rate QP and the correction value TI of the reference drive timing TB return to a state of being stationary at substantially zero.
Therefore, according to Embodiment 1 of the present invention, the conventional problem can be improved.

  As described above, the high-pressure fuel pump control apparatus for an engine according to Embodiment 1 of the present invention includes various sensors 62 to 64 that detect the operating state of the engine 40 and fuel injection that supplies fuel to each combustion chamber of the engine 40. Depending on the operating state of the valve 39, the high-pressure fuel pump 20 that supplies pressurized fuel to the fuel injection valve 39, the flow rate control valve 10 for adjusting the fuel discharge amount Q of the high-pressure fuel pump 20, and the engine 40 A target pressure determining means 601 for determining the target pressure PO, a fuel pressure sensor 61 for detecting the fuel pressure PF supplied from the high pressure fuel pump 20 to the fuel injection valve 39, and a pressure deviation ΔPF between the target pressure PO and the fuel pressure PF are calculated. The pressure deviation calculating means 602 and the pressure deviation ΔPF are multiplied by a proportional coefficient KP to calculate a pressure deviation compensation flow rate QP necessary to make the pressure deviation ΔPF zero. A force error compensation quantity calculation means 603, according to the operating state of the engine 40, and a fuel injection quantity computing means 604 for computing a fuel injection quantity QF from the fuel injection valve 39.

  Further, the high pressure fuel pump control apparatus for an engine according to the first embodiment of the present invention adds the pressure deviation compensation flow rate QP and the fuel injection amount QF to determine the target fuel discharge amount QO of the high pressure fuel pump 20. Using the fuel discharge amount determining means 605, the map storage means for storing the fuel discharge amount characteristic indicating the relationship between the target fuel discharge amount QO and the drive timing of the flow control valve 10 in advance, and the fuel discharge amount characteristic, Reference drive timing determination means 606 for determining the reference drive timing TB of the flow rate control valve 10 corresponding to the amount QO, and drive timing correction for calculating the correction value TI of the reference drive timing TB according to the direction of the sign of the pressure deviation ΔPF The flow rate for driving the flow rate control valve 10 at the final drive timing TD corrected by the means 607 and the drive timing correction means 607 And a valve driving means 609.

  According to Embodiment 1 of the present invention, in order to determine the valve closing timing of the flow control valve 10 according to the above configuration, first, after the pressure deviation ΔPF is calculated, it is necessary to make the pressure deviation ΔPF zero. After the pressure deviation compensation flow rate QP is calculated and the fuel injection amount QF is calculated, the pressure deviation compensation flow rate QP and the fuel injection amount QF are added to determine the target fuel discharge amount QO of the high-pressure fuel pump.

That is, in the first embodiment of the present invention, the proportional control calculated based on the pressure deviation ΔPF is not the feedback proportional term DP of the valve closing timing as in the prior art, but the feedback proportional of the target fuel discharge amount QO. It is calculated as a term (pressure deviation compensation flow rate QP).
Further, the fuel injection amount QF is calculated not as the feedforward term DF at the valve closing timing as in the prior art but as the feedforward term of the target fuel discharge amount QO.

Thereafter, the reference drive timing determining means 606 converts the target fuel discharge amount QO into the reference drive timing TB of the flow control valve using the fuel discharge amount characteristic.
At this time, the difference in the fuel discharge rate efficiency that changes according to the engine speed NE and the target pressure PO is prepared, for example, by preparing a plurality of fuel discharge amount characteristic data in advance for each engine speed NE and the target pressure PO. The fuel discharge amount characteristic data corresponding to the detected engine rotational speed NE and the target pressure PO is selected and corrected.

  When the fuel pressure PF does not coincide with the target pressure PO even though the valve closing timing is controlled at the reference drive timing TB, the reference drive timing TB is determined by the correction value TI corresponding to the sign direction of the pressure deviation ΔPF. Is corrected to a value on the advance side or retard side, and the flow control valve 10 is driven and controlled at the final drive timing TD after the correction.

As described above, the fuel discharge amount characteristic (FIG. 5) is obtained by using the target fuel discharge amount QO obtained by adding the pressure deviation compensation flow rate QP necessary to make the pressure deviation ΔPF zero and the fuel injection amount QF. The reference drive timing TB is determined based on the above, and the final valve closing timing TD is controlled by correcting the reference drive timing TB with the correction value TI calculated according to the sign direction of the pressure deviation ΔPF. Thus, it is possible to control the discharge of the appropriate fuel discharge amount Q over the entire area of the fuel discharge amount characteristic.
In addition, by avoiding an extended period in which the fuel pressure PF and the target pressure PO do not coincide with each other and obtaining optimum combustion performance, dribbling and exhaust gas can be improved.

  Further, by limiting the correction value TI of the reference drive timing TB to a predetermined range set in advance, the correctable range of the reference drive timing TB is set within the maximum timing variation assumed during normal operation. The correction value TI is not set to an abnormal value.

Embodiment 2. FIG.
In the first embodiment, the update condition of the correction value TI in the drive timing correction unit 607 has not been described in detail. However, as described above, the drive timing correction unit 607, for example, the change amount ΔPF of the pressure deviation ΔPF. When / dt is equal to or less than the predetermined change amount KD, when the target fuel discharge amount QO indicates a value within the linear characteristic range of the fuel discharge amount characteristic, or when the engine 40 indicates the idle operation state, the reference drive timing TB The update of the correction value TI is permitted.

Next, the control operation for determining the update permission flag F (the update condition of the correction value TI) according to the second embodiment of the present invention will be described with reference to the flowchart of FIG. 6 together with FIGS.
FIG. 6 specifically shows the update permission flag F determination process used in step S107 described above (see FIG. 3).
The update permission flag F indicates whether or not the update of the correction value TI of the reference drive timing TB is permitted.

6, first, the change amount calculation means 610 calculates the change amount ΔPF / dt of the pressure deviation ΔPF calculated in step S103 described above (FIG. 3) (step S201).
The change amount ΔPF / dt of the pressure deviation ΔPF is not limited to the change amount ΔPF / dt per unit time, and the time change rate of the moving average value of the pressure deviation Δ or the previous value of the calculated pressure deviation ΔPF The deviation of the value this time can be adopted.

Subsequently, it is determined whether or not the absolute value | ΔPF / dt | of the change amount ΔPF / dt is equal to or less than the predetermined change amount KD (step S202), and | ΔPF / dt |> KD (ie, NO) is determined. Then, it is assumed that the pressure deviation ΔPF is still in the process of changing, and the process proceeds to step S207 described later.
On the other hand, if it is determined in step S202 that | ΔPF / dt | ≦ KD (ie, YES), it is assumed that the pressure deviation ΔPF has not changed so much, and in step S105 described above (FIG. 3). The determined target fuel discharge amount QO is read (step S203).

Subsequently, it is determined whether or not the target fuel discharge amount QO shows a value within the linear characteristic range of the fuel discharge amount characteristic (QLL <QO <QHH in FIG. 5) (step S204). If it is determined that the value falls within the linear characteristic range (that is, YES), the update permission flag F is set to “1” (step S208), and the process routine of FIG. 6 is exited.
As a result, when the target fuel discharge amount QO indicates a value within the linear characteristic range (QLL <QO <QHH), the processing in steps S108 to S111 described above (FIG. 3) is executed, and the reference drive timing TB is set. The correction value TI is updated.

  On the other hand, if it is determined in step S204 that the target fuel discharge amount QO is not within the linear characteristic range (QLL <QO <QHH) (that is, NO), then the idle determination flag Fi is read (step S205). Then, it is determined whether or not the engine 40 is in the idling operation state depending on whether or not Fi = 1 (step S206).

If it is determined in step S206 that Fi = 1 (that is, YES), the update permission flag F is set to “1” (step S208), and the process routine of FIG. 6 is exited.
As a result, even when the target fuel discharge amount QO is not within the linear characteristic range (QLL <QO <QHH), when the engine 40 is in the idle state, the processes of steps S108 to S111 described above are executed. Then, the correction value TI of the reference drive timing TB is updated.

On the other hand, if it is determined in step S206 that Fi = 0 (that is, NO), the update permission flag F is reset to “0” (step S207), and the processing routine of FIG. 6 is exited.
As a result, when the change amount ΔPF / dt of the pressure deviation ΔPF is large (| ΔPF / dt |> KD), the target fuel discharge amount QO is not within the linear characteristic range (QLL <QO <QHH), and the engine In any of the cases where 40 is not in the idle operation state (Fi = 0), the process of steps S108 to S111 is passed without being executed, and the correction value TI of the reference drive timing TB is updated. Disappear.

As described above, according to the second embodiment of the present invention, the drive timing correction means 607 determines that the target fuel discharge amount QO is within the linear characteristic range of the fuel discharge amount characteristic (FIG. 5) (QLL <QO <QHH). Is updated, the correction value TI of the reference drive timing TB is updated.
That is, the correction value TI is updated only within the linear characteristic range (a range having a substantially linear characteristic) of the fuel discharge amount characteristic stored in advance, and the update of the correction value TI is interrupted outside the linear characteristic range. .
Therefore, in the high-pressure fuel pump 20, when the deviation occurs with respect to the actual operation position of the plunger 22, it is avoided that the variation in the correction value TI of the reference drive timing TB is expanded, and the final drive is performed. Variations in timing TD can be suppressed.

Here, with reference to the explanatory diagram of FIG. 7 corresponding to FIG. 5 described above, a supplementary explanation will be given of the effect of suppressing variation in the final drive timing TD when the linear characteristic range is set as the update condition.
In FIG. 7, there is a deviation with respect to the normal fuel discharge amount characteristic (see the solid line) where there is no deviation and the operation position of the plunger 22 with respect to the angular direction (left-right direction in FIG. 7). The fuel discharge amount characteristics (see the one-dot chain line) are shown.

In the normal fuel discharge amount characteristic (solid line) in FIG. 7, the reference drive timing TB within the linear characteristic range (QLL <QO <QHH) is the operating point A, and the reference drive timing is outside the linear characteristic range (QO> QHH). Let TB be the operating point B.
At this time, if a deviation has occurred with respect to the operating position of the plunger 22, the final drive timing TD is obtained by calculating the correction value TIa for the operating point A, so that the actual fuel discharge amount characteristic is obtained. It is corrected to the position of the operating point a on (see the one-dot chain line).
If the calculation result of the target fuel discharge amount QO has a fluctuation range ΔQ, the final drive timing TD is expected to vary within the fluctuation range ΔTa with the operating point a as the center.

Similarly, when a deviation has occurred with respect to the operation position of the plunger 22, the final drive timing TD is obtained by calculating the correction value TIb for the operation point B, so that the actual fuel discharge amount characteristic is obtained. The position is corrected to the position of the operating point b on (see the dashed line).
At this time, if the calculation result of the target fuel discharge amount QO similarly has a fluctuation range ΔQ, the final drive timing TD is expected to vary within the fluctuation range ΔTb with the operating point b as the center.

As apparent from FIG. 7, the variation width ΔTb of the correction value TIb outside the linear characteristic range (QO> QHH) is larger than the variation width ΔTa of the correction value TIa within the linear characteristic range (QLL <QO <QHH). Will be bigger.
In consideration of this characteristic, outside the linear characteristic range of the fuel discharge amount characteristic (QO> QHH), the update of the correction value TI of the reference drive timing TB is interrupted to increase the variation in the final drive timing TD. It can suppress and it can suppress that the fluctuation | variation of the fuel pressure PF becomes large.

Further, according to the second embodiment of the present invention, the idle detection unit 64 that detects the idle operation state of the engine 40 is provided, and the drive timing correction unit 607 is configured to perform the reference drive timing when the idle operation state is detected. The correction value TI of TB is updated.
As described above, the feedback correction value TI for the reference drive timing TB is updated only in the idle operation state in which the absolute amount and change amount of the fuel injection amount QF are small, and in the non-idle operation state, the reference drive timing TB is corrected. By interrupting the update of the value TI, the deviation of the correction value TI is avoided and the variation of the final drive timing TD is suppressed when a deviation occurs with respect to the actual operation position of the plunger 22. can do.

Here, with reference to the explanatory diagram of FIG. 8 corresponding to FIG. 5 described above, a supplementary explanation will be given of the effect of suppressing variation in the final drive timing TD when the idle operation state is set as the update condition.
In FIG. 8, there is a deviation with respect to the normal fuel discharge amount characteristic (see the solid line) where there is no deviation and the operation position of the plunger 22 with respect to the angular direction (left-right direction in FIG. 8). The fuel discharge amount characteristics (see the one-dot chain line) are shown.

In the regular fuel discharge amount characteristic (solid line) in FIG. 8, the reference drive timing TB in the idle operation state is an operation point D, and the reference drive timing TB in the non-idle operation state is an operation point E.
At this time, if a deviation has occurred with respect to the operation position of the plunger 22, the correction value TId is calculated for the operation point D, so that the final drive timing TD is the actual fuel discharge amount characteristic. It is corrected to the position of the operating point d on (one-dot chain line).
Further, if the calculation result of the target fuel discharge amount QO has the fluctuation range ΔQd, the final drive timing TD is expected to vary within the fluctuation range ΔTd with the operating point d as the center.
Note that, in the idle operation state, the engine 40 is in a steady operation, and the fuel injection amount QF and the target pressure PO are substantially constant, so the fluctuation range ΔQd of the target fuel discharge amount QO is relatively small.

Similarly, by calculating the correction value TIe with respect to the operating point E, the final drive timing TD is an actual fuel discharge amount characteristic (one-dot chain line) that is deviated from the operating position of the plunger 22. ) Is corrected to the position of the upper operating point e.
If the calculation result of the target fuel discharge amount QO has a fluctuation range ΔQe, the final drive timing TD is expected to vary within the fluctuation range ΔTe around the operating point e.

However, in the non-idle operation state, the operation state is not constant compared to the idle operation state, and the fuel injection amount QF and the target pressure PO change from moment to moment, so the fluctuation range ΔQe of the target fuel discharge amount QO is This is considered to be larger than the fluctuation range ΔQd in the operating state.
Therefore, as apparent from FIG. 8, with respect to the correction value TI of the reference drive timing TB, the variation range ΔTe in the non-idle operation state is larger than the variation range ΔTd in the idle operation state.

  In consideration of this characteristic, in the non-idle operation state, by interrupting the update of the correction value TI of the reference drive timing TB, the variation in the final drive timing TD is suppressed, and the fluctuation of the fuel pressure PF is changed. It is possible to suppress the increase.

In addition, according to the second embodiment of the present invention, the change amount calculation means 610 for calculating the change amount ΔPF / dt of the pressure deviation ΔPF is provided, and the drive timing correction means 607 has the change amount ΔPF / dt of the pressure deviation ΔPF. When the absolute value | ΔPF / dt | indicates a predetermined change amount KD or less, the correction value TI of the reference drive timing TB is updated.
That is, the drive timing correction means 607 updates the correction value TI when | ΔPF / dt | ≦ KD (when both the target pressure PO and the fuel pressure PF are in a certain state), and | ΔPF / dt |> In the case of KD (when either one or both of the target pressure PO and the fuel pressure PF have changed to some extent), the update of the correction value TI is interrupted.

  As a result, when the pressure deviation ΔPF occurs, in the transient state where the fuel pressure PF has not changed sufficiently, the reference drive timing TB is not prepared by the pressure deviation compensation flow rate QP calculated by the pressure deviation compensation flow rate calculation means 603. Therefore, the overshoot of the fuel pressure PF immediately after the pressure deviation PF returns to zero can be suppressed.

  In FIG. 6, among the three determination conditions (steps S202, S204, and S206), the change amount ΔPF / dt (step S202), the condition within the linear characteristic range (step S204), or the idle operation state (step S206). However, any one of the conditions or a combination of the two conditions may be used.

Embodiment 3 FIG.
In the first and second embodiments, the specific processing procedure of the flow rate decrease determination unit 611 and the reference drive timing determination unit 606 is not mentioned, but is executed as shown in the flowchart of FIG.
Next, a specific control operation according to the third embodiment of the present invention will be described with reference to FIGS. 1 to 5 and FIG.

  As described above, when the target fuel discharge amount QO indicates a value in a predetermined low flow rate region (in the range of QLL <QO <QLH in FIG. 10 to be described later), the flow rate decrease determination unit 611 is a drive timing correction unit. The correction value TI updated by 607 is stored as a low flow rate region correction value TIL, and the target fuel discharge amount QO indicates a value in a predetermined high flow rate region (in the range of QHL <QO <QHH in FIG. 10 described later). Sometimes, the updated correction value TI is stored as the high flow rate region correction value TIH.

Further, the flow rate decrease determination means 611 is a high-pressure fuel pump for the drive timing of the flow control valve 10 when the high flow rate correction value TIH indicates a relatively advanced value rather than the low flow rate correction value TIL. It is determined that the fuel flow rate Q of 20 is low, and the determination result is input to the reference drive timing determination means 606.
The reference drive timing determination unit 606 determines the target fuel discharge amount QO of the high-pressure fuel pump 20 with respect to the drive timing of the flow rate control valve 10 in the fuel discharge amount characteristic data when the flow rate decrease determination unit 611 determines the flow rate decrease state. Update the value to a value less than the current value.

In FIG. 9, the control function of the flow rate decrease determination unit 611 and the control function of the reference drive timing determination unit 606 are shown.
In FIG. 9, first, the target fuel discharge amount QO determined in step S105 described above (see FIG. 3) is read (step S301), and the correction value of the reference drive timing TB after the limiting process is completed in step S113 described above. TI is read (step S302), and it is determined whether or not the target fuel discharge amount QO is within a predetermined low flow rate region (QLL <QO <QLH) (step S303).

If it is determined in step S303 that the target fuel discharge amount QO is not in the low flow rate range (that is, NO), the process immediately proceeds to the next determination process (step S306).
On the other hand, if it is determined in step S303 that the target fuel discharge amount QO is in the low flow rate region (that is, YES), the correction value TI is stored as the low flow region correction value TIL (step S304), and the low flow region correction is performed. The flag FL is set to “1” (step S303).

Subsequently, it is determined whether or not the target fuel discharge amount QO read in step S301 is in a predetermined high flow rate range (QHL <QO <QHH) (step S306), and the target fuel discharge rate QO is in the high flow rate range. If it is determined that it is not present (that is, NO), the process immediately proceeds to the next determination process (step S309).
On the other hand, if it is determined in step S306 that the target fuel discharge amount QO is in the high flow rate region (that is, YES), the correction value TI is stored as the high flow region correction value TIH (step S307), and the high flow region correction is performed. The flag FH is set to “1” (step S308).

  Next, it is determined whether or not both the low flow region correction flag FL and the high flow region correction flag FH are set to “1” (step S309), and the low flow region correction flag FL or the high flow region correction flag FH is determined. If it is determined that at least one of these is reset to “0” (that is, NO), it is assumed that both the low flow region correction value TIL and the high flow region correction value TIH have not been stored, and FIG. 9 is exited.

  On the other hand, if it is determined in step S309 that both the low flow region correction flag FL and the high flow region correction flag FH are set to “1” (that is, YES), both the low flow region and the high flow region are set. Since the correction values TIL and TIH in the above are already stored, the low flow region value TIL and the high flow region correction value TIH are compared, and the high flow region correction value TIH is more than the low flow region correction value TIL. It is determined whether or not a relatively advanced value (TIL> TIH) (step 310).

If it is determined in step S310 that TIL ≦ TIH (that is, NO), it is considered that the flow rate reduction state has not occurred, and the fuel discharge amount characteristic data used in the reference drive timing determination unit 606 is not updated. The processing routine of FIG. 9 is exited.
On the other hand, if it is determined in step S310 that TIL> TIH (that is, YES), the flow rate control valve 10 is driven with fuel discharge amount characteristic data stored in advance, assuming that a low flow rate state has occurred. The target fuel discharge amount QO for the timing is updated to a value smaller than the current value (step S311), and both the low flow region correction flag FL and the high flow region correction flag FH are reset to “0” (step S312). ), And exits the processing routine of FIG.

  As described above, the high flow rate region correction value TIH when the target fuel discharge amount QO is in the high flow rate region is relatively advanced than the low flow rate region correction value TIL when the target fuel discharge amount QO is in the low flow rate region. When the value on the corner side is indicated, the actual fuel with respect to the drive timing is updated by updating the value of the target fuel discharge amount QO with respect to the drive timing of the flow control valve 10 in the fuel discharge amount characteristic to a value smaller than the current value. The flow rate reduction state of the discharge amount Q (for example, due to aging and wear of the pump cam 25) can be detected, and the characteristic data corresponding to the actual fuel discharge amount characteristic when the flow reduction state occurs Can be updated.

  That is, according to the third embodiment of the present invention, it is possible to detect the flow rate decrease state of the fuel discharge amount Q with respect to the drive timing and to store in advance so as to match the fuel discharge amount characteristic when the discharge amount decreases. Since the fuel discharge amount characteristic is updated, the target fuel discharge amount QO necessary for matching the fuel pressure PF to the target pressure PO can be appropriately calculated even if the flow rate of the fuel discharge amount Q is reduced. It is possible to maintain good controllability for making the fuel pressure PF coincide with the target pressure PO.

Here, a supplementary description will be given of the effect of improving the controllability by updating the fuel discharge amount characteristic with reference to the explanatory diagrams of FIGS. 10 and 11 corresponding to FIG. 5 described above.
FIG. 11 shows characteristics TQ2, TQ3, and TQ4 (dashed line, one-dot chain line, two-dot chain line) that are sequentially updated with respect to the normal fuel discharge amount characteristic TQ1 (see the solid line) when the flow rate decreases. Yes.
In FIG. 10, with respect to the discharge amount direction (vertical direction in FIG. 10), a normal fuel discharge amount characteristic (see a solid line) that does not have a deviation, and a fuel discharge amount characteristic when a flow rate decrease state occurs. (See the two-dot chain line).

Also, in FIG. 10, in the normal fuel discharge amount characteristic, the reference drive timing TB when the target fuel discharge amount QO is in the low flow rate region (QLL <QO <QLH) is the operating point F, and the target fuel discharge amount QO Is the operating point G, which is the reference driving timing TB when is in the high flow rate range (QHL <QO <QHH).
At this time, when the flow rate drop occurs in the fuel discharge amount Q, the operating point F of the reference drive timing TB is corrected by the correction value TIL, and the final drive timing TD is the actual fuel discharge when the flow rate drop occurs. It is corrected to the position of the operating point f on the quantity characteristic (two-dot chain line).

  Similarly, the operating point G on the normal fuel discharge amount characteristic (solid line) is also corrected by the correction value TIH, and the final drive timing TD is on the actual fuel discharge amount characteristic (two-dot chain line) when the flow rate decreases. Is corrected to the position of the operating point g.

As is clear from FIG. 10, when the flow rate drop state occurs, the flow rate in the high flow rate range (QHL <QO <QHH) is higher than the low flow rate range correction value TIL in the low flow rate range (QLL <QO <QLH). The area correction value TIH is larger on the advance side.
Therefore, based on this characteristic, when it is determined that the high flow rate correction value TIH is larger on the advance side than the low flow rate correction value TIL, the fuel discharge amount Q is in the flow rate reduced state. Can be regarded as

Further, when it is determined that the flow rate of the fuel discharge amount Q with respect to the drive timing is reduced, the target fuel discharge amount QO with respect to the drive timing of the flow control valve 10 in the fuel discharge amount characteristic is updated to a value smaller than the current value. Thus, as shown in FIG. 11, the regular fuel discharge amount characteristic TQ1 (solid line) is sequentially updated to, for example, the characteristics TQ2 and TQ3, and updated to the final fuel discharge amount characteristic TQ4.
Thereafter, the target fuel discharge amount QO is converted into the reference drive timing TB using the data of the final fuel discharge amount characteristic TQ4. Therefore, even when the flow rate is reduced, the reference drive timing TB is corrected. The burden of the feedback amount of the value TI is reduced.

It is a block block diagram which shows the fuel supply system which concerns on Embodiment 1 of this invention. It is a functional block diagram for implement | achieving the control function which concerns on Embodiment 1 of this invention. It is a flowchart which shows the control action which concerns on Embodiment 1 of this invention. It is a timing chart which shows the control action at the time of the sudden change of the target pressure in Embodiment 1 of this invention. It is explanatory drawing which shows the fuel discharge amount characteristic relevant to the control action at the time of the sudden change of the target pressure in Embodiment 1 of this invention. It is a flowchart which shows the control action which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the fuel discharge amount characteristic for demonstrating the effect by Embodiment 2 of this invention. It is explanatory drawing which shows the fuel discharge amount characteristic for demonstrating another effect by Embodiment 2 of this invention. It is a flowchart which shows the control action which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the fuel discharge amount characteristic for demonstrating the effect by Embodiment 3 of this invention. It is explanatory drawing which shows the fuel discharge amount characteristic for demonstrating the effect by Embodiment 3 of this invention. It is explanatory drawing which shows the relationship between the valve closing timing of the flow control valve in the general plunger upward movement period, and fuel discharge amount. It is a timing chart which shows the control action at the time of the sudden change of the target pressure in a prior art. It is explanatory drawing which shows the operating point on the fuel discharge amount characteristic at the time of the sudden change of the target pressure in a prior art. It is a timing chart which shows the control operation for demonstrating the subject at the time of the sudden change of the target pressure in a prior art. It is explanatory drawing which shows the fuel discharge amount characteristic for demonstrating the subject at the time of the sudden change of the target pressure in a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow control valve, 11 Electromagnetic solenoid, 20 High pressure fuel pump, 22 Plunger, 23 Pressurization chamber, 24 Cam shaft, 25 Pump cam, 30 Fuel tank, 33 Low pressure passage, 34 High pressure passage, 36 Accumulation chamber, 39 Fuel injection valve, 40 engine, 60 ECU, 61 fuel pressure sensor, 62 crank angle sensor, 63 accelerator position sensor, 64 idle detection means, 601 target pressure determination means, 602 pressure deviation calculation means, 602a subtractor, 603 pressure deviation compensation flow rate calculation means, 604 Fuel injection amount calculation means, 605 target fuel discharge amount determination means, 606 reference drive timing determination means, 607 drive timing correction means, 608 adder, 609 flow control valve drive means, 610 change amount calculation means, 611 flow rate decrease determination means, NE engine speed, P accelerator pedal depression amount, F update permission flag, Fi idle determination flag, FL low flow region correction flag, FH high flow region correction flag, KI integral coefficient, KP proportional coefficient, PF fuel pressure (fuel pressure detection value), PO target pressure , ΔPF pressure deviation, ΔPF / dt change in pressure deviation, Q fuel discharge amount, QP pressure deviation compensation flow rate, QF fuel injection amount, QO target fuel discharge amount, TB reference drive timing, TI reference drive timing correction value, TIL Low flow rate correction value, TIH High flow rate correction value, TD Final drive timing.

Claims (6)

Various sensors for detecting the operating state of the engine;
A fuel injection valve for supplying fuel to each combustion chamber of the engine;
A high-pressure fuel pump for supplying pressurized fuel to the fuel injection valve;
A flow control valve for adjusting the fuel discharge amount of the high-pressure fuel pump;
Target pressure determining means for determining a target pressure according to the operating state of the engine;
A fuel pressure sensor that detects a pressure of fuel supplied from the high-pressure fuel pump to the fuel injection valve and outputs a fuel pressure detection value;
Pressure deviation calculating means for calculating a pressure deviation between the target pressure and the fuel pressure detection value;
A pressure deviation compensation flow rate calculating means for calculating a pressure deviation compensation flow rate required to make the pressure deviation zero by multiplying the pressure deviation by a proportional coefficient;
A fuel injection amount calculating means for calculating a fuel injection amount from the fuel injection valve in accordance with an operating state of the engine;
A target fuel discharge amount determining means for determining a target fuel discharge amount of the high-pressure fuel pump by adding the pressure deviation compensation flow rate and the fuel injection amount;
Map storage means for storing in advance a fuel discharge amount characteristic indicating a relationship between the target fuel discharge amount and the drive timing of the flow control valve;
Reference drive timing determining means for determining a reference drive timing of the flow rate control valve corresponding to the target fuel discharge amount using the fuel discharge amount characteristic;
Drive timing correction means for performing integration processing according to the direction of the sign of the pressure deviation and calculating a feedback integral correction value of the reference drive timing;
A high-pressure fuel pump control device for an engine, comprising: a flow rate control valve drive unit that drives the flow rate control valve at a final drive timing after the reference drive timing is corrected by the feedback integral correction value .   The said drive timing correction | amendment means updates the correction value of the said reference drive timing, when the said target fuel discharge amount shows the value within the linear characteristic range of the said fuel discharge amount characteristic. Engine high pressure fuel pump control device. Comprising idle detection means for detecting an idle operation state of the engine,
3. The high-pressure fuel pump control for an engine according to claim 1, wherein the drive timing correction unit updates the correction value of the reference drive timing when the idle operation state is detected. apparatus. A change amount calculating means for calculating a change amount of the pressure deviation;
The drive timing correction means updates the correction value of the reference drive timing when the change amount of the pressure deviation indicates a predetermined change amount or less. The high-pressure fuel pump control device for an engine according to the item. A flow rate decrease determination means for determining a flow rate decrease state of the fuel discharge amount of the high pressure fuel pump with respect to the drive timing of the flow rate control valve;
The flow rate drop determination means is
When the target fuel discharge amount indicates a predetermined low flow rate range value, the correction value updated by the drive timing correction means is stored as a low flow rate range correction value,
When the target fuel discharge amount indicates a predetermined high flow rate range value, the correction value updated by the drive timing correction means is stored as a high flow rate range correction value,
When the high flow rate correction value indicates a relatively advanced value rather than the low flow rate correction value, the flow rate decrease state of the fuel discharge amount of the high-pressure fuel pump with respect to the drive timing of the flow control valve Is determined to have occurred,
The reference drive timing determining means determines a target fuel discharge amount of the high-pressure fuel pump with respect to a drive timing of the flow control valve in the fuel discharge amount characteristic when the flow reduction state is determined by the flow reduction determination means. The high pressure fuel pump control device for an engine according to any one of claims 1 to 4, wherein the value is updated to a value smaller than a current value.   The high-pressure fuel pump for an engine according to any one of claims 1 to 5, wherein the correction range of the reference drive timing is set within a variation of a maximum timing assumed in a normal state. Control device.

Images