JP4211732B2 - Fuel supply device for internal combustion engine - Google Patents

Description

  The present invention relates to a fuel supply device for an internal combustion engine that controls an actual fuel pressure in a pressure accumulating chamber for storing fuel to a target fuel pressure in order to supply fuel at a predetermined pressure to a fuel injection valve.

  An intake port injection type internal combustion engine that injects fuel into an intake passage is well known. In this type of internal combustion engine, the fuel supplied to the fuel injection valve is usually stored in a delivery pipe (pressure accumulator), and the actual fuel pressure (fuel pressure) in the delivery pipe is controlled to a target fuel pressure. In addition, a fuel supply device is provided that sets the target fuel pressure higher by a predetermined value than the intake pressure of the engine. This is because the fuel injection amount per unit time when the fuel injection valve is opened is proportional to the square root of the difference between the pressure in the delivery pipe and the intake pressure. For this reason, fuel injection control can be suitably performed by making the differential pressure between the fuel pressure in the delivery pipe and the intake pressure substantially constant.

  However, by injecting fuel through the fuel injection valve, the fuel in the delivery pipe is consumed and the fuel pressure in the delivery pipe is also reduced. Therefore, conventionally, for example, as can be seen in Patent Document 1, a fuel supply device has been proposed in which the same amount of fuel as that injected via a fuel injection valve is supplied to a delivery pipe. Patent Document 2 below also proposes a fuel supply device that performs feedback control so that the fuel pressure in the delivery pipe becomes the target fuel pressure.

  By the way, the intake pressure of the internal combustion engine varies greatly depending on its operating condition. However, the fuel supply device of Patent Document 1 cannot control the fuel pressure in the delivery pipe according to the change in the intake pressure. On the other hand, in Patent Document 2, although the actual fuel pressure in the delivery pipe can be controlled to the target fuel pressure, the control performance in the transition period until the actual fuel pressure is set to the target fuel pressure is deteriorated. . This is because when the target fuel pressure changes due to the change of the intake pressure, the fuel supply device of Patent Document 2 performs feedback control according to the difference between the actual fuel pressure and the target fuel pressure. For this reason, when the target fuel pressure changes, it is inevitable that a large difference once occurs between the actual fuel pressure and the target fuel pressure.

  For this reason, conventionally, when a large difference occurs between the target fuel pressure and the actual fuel pressure due to a large change in the intake pressure as described above, the fuel injection time in the fuel injection control is changed to the actual fuel pressure. A correction process was also performed accordingly. However, since the timing for detecting the fuel pressure, the calculation timing for the fuel injection time, and the calculation timing for the correction amount for the injection time do not generally match, it is extremely difficult to accurately inject the required amount of fuel depending on the correction for the fuel injection time. It has become difficult.

  Further, when the fuel pressure in the delivery pipe is different from the target fuel pressure, the fuel spray shape is also different, which leads to deterioration of exhaust characteristics.

In addition to the fuel supply device provided in the intake port injection type internal combustion engine, the actual fuel pressure in the pressure accumulating chamber for storing the fuel is controlled to the target fuel pressure in order to supply the fuel injection valve with fuel of a predetermined pressure. For those who do, these facts are generally common.
JP 2002-242784 A JP-A-6-173805

  A problem to be solved by the present invention is a fuel supply apparatus for an internal combustion engine that controls an actual fuel pressure in a pressure accumulating chamber for storing fuel to a target fuel pressure in order to supply fuel at a predetermined pressure to a fuel injection valve. It is difficult to control the actual fuel pressure to the target fuel pressure. An object of the present invention is to provide a fuel supply device that can appropriately follow the actual fuel pressure with the target fuel pressure even when the target fuel pressure changes greatly.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  The means 1 includes setting means for setting an operation amount for controlling the actual fuel pressure to the target fuel pressure based on a change amount of the target fuel pressure.

  When the target fuel pressure changes greatly, the controllability of the transient fuel pressure is deteriorated when the actual fuel pressure is controlled to the target fuel pressure.

  In this regard, in the above configuration, by setting the manipulated variable based on the target amount of change in fuel pressure, the actual fuel pressure is set as the target in anticipation of an increase in the difference between the target fuel pressure and the actual fuel pressure. The fuel pressure can be controlled. For this reason, the transient fuel pressure controllability when the target fuel pressure changes can be greatly improved. Furthermore, since the transient fuel pressure controllability can be greatly improved, the exhaust characteristics can also be improved.

  In the means 2, in the means 1, the target fuel pressure is calculated based on the intake pressure of the engine.

  The intake pressure varies greatly depending on the operating state of the engine. For this reason, when the target fuel pressure is calculated based on the intake pressure, the target fuel pressure also changes greatly. For this reason, in the said structure, the effect of the means 1 can be show | played suitably.

  In the means 3, in the means 1 or 2, the manipulated variable has a feed forward term set based on the change amount and a feedback term for feedback control of the actual fuel pressure to the target fuel pressure. I made it.

  In the above configuration, in addition to the feedforward term set based on the target fuel pressure change amount, the manipulated variable has a feedback term for feedback control of the actual fuel pressure to the target fuel pressure. The fuel pressure can be suitably controlled by the target fuel pressure.

  The means 4 further comprises means for detecting a differential pressure between the fuel pressure in the accumulator chamber and the intake pressure of the engine in the means 3, and the feedback control feeds back the detected differential pressure to a target differential pressure. The target fuel pressure is calculated by adding the intake pressure to the target differential pressure.

  In the above configuration, the detected differential pressure can be directly used in feedback control. Further, since the target fuel pressure is calculated by adding the intake pressure to the detected differential pressure, the target amount of change in the fuel pressure can be acquired based on this.

  In the means 5, in order to supply a fuel of a predetermined pressure to the fuel injection valve, the fuel supply of the internal combustion engine for controlling the actual fuel pressure in the pressure accumulating chamber for storing the fuel to a target fuel pressure calculated based on a predetermined parameter. In the apparatus, setting means is provided for setting an operation amount for controlling the actual fuel pressure to the target fuel pressure based on a change amount of the parameter.

  When the target fuel pressure changes greatly, the controllability of the transient fuel pressure is deteriorated when the actual fuel pressure is controlled to the target fuel pressure. On the other hand, the change in the target fuel pressure depends on the change in the parameter used when the target fuel pressure is calculated.

  In this regard, in the above-described configuration, the difference between the target fuel pressure and the actual fuel pressure is increased by setting the operation amount based on the amount of change in the parameter used when the target fuel pressure is calculated. In anticipation, the actual fuel pressure can be controlled to the target fuel pressure. For this reason, the transient fuel pressure controllability when the target fuel pressure changes can be greatly improved. Furthermore, since the transient fuel pressure controllability can be greatly improved, the exhaust characteristics can also be improved.

  In the means 6, in the means 5, the predetermined parameter is an intake pressure of the engine.

  The intake pressure varies greatly depending on the operating state of the engine. For this reason, when the target fuel pressure is calculated based on the intake pressure, the target fuel pressure also changes greatly. For this reason, in the said structure, the effect of the means 5 can be show | played suitably.

  In the means 7, in the means 5 or 6, the manipulated variable has a feedforward term set based on the change amount and a feedback term for feedback control of the actual fuel pressure to the target fuel pressure. I made it.

  In the above configuration, in addition to the feedforward term set based on the change amount of the parameter, the manipulated variable has a feedback term for feedback control of the actual fuel pressure to the target fuel pressure, so that the actual fuel pressure Can be suitably controlled by the target fuel pressure.

  The means 8 further comprises means for detecting a differential pressure between the fuel pressure in the pressure accumulating chamber and the intake pressure of the engine in the means 7, and the feedback control feeds back the detected differential pressure to a target differential pressure. I tried to control it.

  In the above configuration, in actual feedback control, the actual fuel pressure can be controlled to the target fuel pressure without actually calculating the target fuel pressure or the actual fuel pressure.

  In the means 9, in any one of the means 1 to 8, the setting means converts the change amount into a fuel amount required in the pressure accumulating chamber, and converts the converted fuel amount into the manipulated variable. And means.

  The relation between the amount of operation of the actuator for controlling the actual fuel pressure to the target fuel pressure and the amount of fuel supplied to the pressure accumulating chamber is usually determined.

  In this regard, in the above configuration, in order to set the operation amount of the actuator, the operation amount can be easily set by converting the change amount into a fuel amount required in the pressure accumulating chamber.

  In the means 10, in any one of the means 1 to 9, the operation amount includes a feed forward term set based on the amount of fuel injected through the fuel injection valve.

  In the above configuration, since the feed forward term set based on the amount of fuel injected through the fuel injection valve is included, it is possible to compensate for this in anticipation of a decrease in fuel pressure caused by fuel injection through the fuel injection valve. it can. For this reason, an actual fuel pressure can be made to follow a target fuel pressure more suitably.

  In the case of any one of the means 2 to 4 and 6 to 10 and having the structure of the means 2 or 6, the fuel injection valve is for injecting fuel into the intake passage of the engine. Is desirable.

  In the case of injecting fuel into the intake passage of an internal combustion engine, control having a strong correlation with the intake pressure is performed, for example, the differential pressure between the target fuel pressure and the intake pressure is substantially constant. For this reason, in the said structure, since the target fuel pressure will change a lot according to intake pressure, the effect of the structure of means 2-4 and means 6-10 can be show | played more suitably.

(First embodiment)
A first embodiment in which a fuel supply device for an internal combustion engine according to the present invention is applied to a fuel supply device provided in an intake port injection gasoline engine will be described below with reference to the drawings.

  FIG. 1 shows a fuel supply device according to this embodiment and a configuration around it.

  The internal combustion engine 1 which is a gasoline engine is a multi-cylinder (for example, four cylinders) internal combustion engine, and only one cylinder is shown in FIG. A fuel injection valve 4 that injects and supplies fuel is provided in each intake passage 2 (more precisely, in the vicinity of the intake port) of each cylinder of the internal combustion engine 1. The fuel stored in the delivery pipe 6 is supplied to the fuel injection valves 4 provided corresponding to the respective cylinders of the internal combustion engine 1. The delivery pipe 6 is supplied with the fuel pumped up from the fuel tank 8 by the fuel pump 10 through the fuel filter 12. The fuel pump 10 is driven by a fuel pump controller 14.

  On the other hand, the electronic control unit 20 includes a central processing unit and a memory, takes in the detection values of various sensors that detect various operating states of the internal combustion engine 10, and controls the internal combustion engine 10 based on this. Specifically, the electronic control device 20, for example, an intake pressure sensor 22 that detects the pressure (intake pressure) in the intake passage 2 or a crank that detects the rotation angle of the crankshaft 24 that is the output shaft of the internal combustion engine 1. The detected values of the angle sensor 26 and the fuel pressure sensor 28 for detecting the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure are taken in. Based on these detected values, for example, by operating the fuel pump controller 14, the actual fuel pressure in the delivery pipe 6 is controlled to a target fuel pressure.

  Here, the process of controlling the fuel pressure in the delivery pipe 6 according to the present embodiment to the target fuel pressure will be described in detail.

  FIG. 2 shows functional blocks of the above control, and FIG. 3 shows the processing procedure. Incidentally, the process shown in FIG. 3 is repeatedly executed by the electronic control unit 20 at a predetermined cycle.

  The processing of steps S10 to S30 in the series of processing shown in FIG. 3 corresponds to the processing of the part surrounded by the broken line in FIG.

  That is, in step S10, the target fuel pressure (target fuel pressure Pt) is calculated based on the intake pressure Pm detected by the intake pressure sensor 22 and the rotational speed Ne of the crankshaft 24 detected by the crank angle sensor 26. To do. Here, the target fuel pressure Pt is an absolute pressure.

  In the present embodiment, the target fuel pressure Pt is basically set to a value higher than the intake pressure by a predetermined value, but the predetermined value is slightly variably set according to the operating state of the internal combustion engine 1. Therefore, the target differential pressure (target differential pressure DF), which is the differential pressure between the target fuel pressure and the intake pressure, is slightly variably set according to the rotational speed Ne of the crankshaft 24 and the intake pressure Pm. Specifically, the map calculation of the target differential pressure DF is performed using the map DF (Ne, Pm) that defines the relationship between the rotational speed Ne and the intake pressure Pm and the target differential pressure DF. Then, the target fuel pressure Pt is calculated by adding the target differential pressure DF and the intake pressure Pm.

  In the subsequent step S20, a target fuel pressure change amount ΔPt is calculated. That is, the target fuel pressure change amount ΔPt is calculated by subtracting the previously calculated target fuel pressure Pt (i−1) from the currently calculated target fuel pressure Pt (i).

  Furthermore, in step S30, the change amount ΔPt of the target fuel pressure is converted into a fuel amount ΔFp required to be supplied to the delivery pipe 6. This conversion is performed as follows.

  Assuming that the volume of the fuel passage from the fuel pump 10 to the fuel injection valve 4 is V and the elastic modulus is E, the change in the fuel pressure in the fuel passage is the amount of change in the fuel in the delivery pipe 6 divided by (V / E). It will be a thing.

  However, in the present embodiment, the required fuel amount is calculated in units of a predetermined time (for example, “1 s”), and the predetermined time is different from the calculation period (for example, “16 ms”) of the target fuel pressure change amount ΔPt. For this reason, the change of the fuel pressure calculated by dividing by the above (V / E) is converted into the change of the fuel pressure in a predetermined time unit. This conversion coefficient is the coefficient α (for example, “0.016”) shown in FIG. For this reason, the following formula is established.

ΔPt = ΔFp × (E / (α × V))
Here, by defining “(α × V) / E” as a proportional coefficient K, “ΔFp = K × ΔPt”. This is the process performed in step S30.

  In the subsequent step S40, the fuel injection amount Finj is calculated. In step S50, the amount of fuel required by feedforward control (feedforward fuel supply amount Fp) is calculated from the amount of fuel supplied to the delivery pipe 6. That is, the fuel required by the feedforward control is added by adding the fuel amount ΔFp required by the change in the target fuel pressure Pt and the fuel injection amount Finj that is the fuel amount required by the fuel injection. The amount Fp is calculated.

  In subsequent step S60, the fuel pressure sensor 28 detects a differential pressure Pf between the fuel pressure in the delivery pipe 6 and the intake pressure.

  In step S70, the feedforward voltage Vp, which is the operation voltage for the feedforward control, among the operation voltages of the fuel pump 10 by the fuel controller 14 is calculated (a fuel / voltage conversion unit in FIG. 2). Specifically, the feedforward voltage Vp is map-calculated from a two-dimensional map of the fuel pressure in the delivery pipe 6 (the sum of the differential pressure Pf and the intake pressure Pm) and the differential pressure between the atmospheric pressure Pa and the feedforward fuel supply amount Fp. . Here, the fuel supply capacity of the fuel pump 10 changes according to the differential pressure between the fuel pressure in the delivery pipe 6 and the atmospheric pressure Pa. For this reason, since the operation voltage cannot be uniquely determined only by the feedforward fuel supply amount Fp, in addition to the feedforward fuel supply amount Fp, the differential pressure between the fuel pressure in the delivery pipe 6 and the atmospheric pressure Pa is set. Based on this, the feedforward voltage Vp is calculated.

  Further, in step S80, an operation voltage (feedback voltage Vpid) for performing feedback control is calculated based on the differential pressure Pf detected by the fuel pressure sensor 28 and the target differential pressure DF. Specifically, this feedback control is PID control (proportional control, integral control, and differential control) as shown in FIG. 2 (PID control unit in FIG. 2).

  In step S90, the final control voltage Vt is calculated based on the feedforward voltage Vp and the feedback voltage Vpid. Specifically, as shown in FIG. 2, first, the total voltage Vtotal is calculated by adding the feedforward voltage Vp and the feedback voltage Vpid. When the total voltage Vtotal is between a predetermined upper limit value (for example, “14V”) and a lower limit value (for example, “0V”), this is set as the final voltage Vt. If the value is the final voltage Vt and falls below the lower limit value, the lower limit value is the final voltage Vt.

  Here, the experimental result concerning the said control is demonstrated using FIGS.

  FIG. 4 shows the case where the above control is performed. FIG. 4A shows the transition of the intake pressure, and FIG. 4B shows the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure (fuel pressure). FIG. 4C shows the transition of the operation voltage when the fuel pump 10 is operated. As shown in the figure, even if the intake pressure Pm changes, the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure (detected value of the fuel pressure sensor 28) hardly changes and follows the target differential pressure DF. .

  On the other hand, FIG. 5 shows the case where the output of the portion indicated by the broken line in FIG. 2 is “0”, in other words, the case where the control of the broken line portion (control related to the calculation of ΔFp) is not performed. ing. Specifically, FIG. 5A shows the transition of the intake pressure, and FIG. 5B shows the transition of the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure (detected value of the fuel pressure sensor 28). (C) shows the transition of the operating voltage when operating the fuel pump 10, respectively. In this case, when the intake pressure Pm changes greatly, the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure (detected value of the fuel pressure sensor 28) also changes.

  Incidentally, FIG. 6 shows a case where only the PID control is performed to control the fuel pressure in the delivery pipe 6 to the target fuel pressure Pt. Specifically, FIG. 6A shows the transition of the intake pressure, and FIG. 6B shows the transition of the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure (detected value of the fuel pressure sensor 28). (C) shows the transition of the operating voltage when operating the fuel pump 10, respectively. In this case, the operating voltage of the fuel pump 10 changes after it is detected that the actual differential pressure Pf is separated from the target differential pressure DF due to the change in the intake pressure Pm. For this reason, when the intake pressure Pm changes greatly, it is inevitable that the actual differential pressure Pf is once largely separated from the target differential pressure DF.

  According to the embodiment described above in detail, the following effects can be obtained.

  (1) The operation voltage for controlling the actual fuel pressure (Pf + Pm) to the target fuel pressure Pt is set based on the change amount ΔPt of the target fuel pressure. Here, when the target fuel pressure Pt changes greatly due to a large change in the intake pressure, the controllability of the transient fuel pressure when controlling the actual fuel pressure to the target fuel pressure Pt may be deteriorated. In this respect, the actual fuel pressure is controlled to the target fuel pressure Pt in anticipation of an increase in the difference between the target fuel pressure Pt and the actual fuel pressure by setting the operation voltage based on the change amount ΔPt of the target fuel pressure. be able to. For this reason, the transient fuel pressure controllability when the target fuel pressure Pt changes can be greatly improved. Furthermore, since the transient fuel pressure controllability can be greatly improved, the exhaust characteristics can also be improved.

  (2) The change amount ΔPt of the target fuel pressure is converted into the fuel amount required in the delivery pipe 6, and the converted fuel amount is converted into the operation voltage. Here, the relationship between the operating voltage of the fuel pump 10 and the amount of fuel supplied to the delivery pipe 6 is determined. Therefore, the operation voltage can be easily set by once converting the change amount ΔPt of the target fuel pressure into the fuel amount ΔFp required in the delivery pipe 6.

  (3) The operation voltage includes a feed-forward term set based on the fuel amount Finj injected through the fuel injection valve 4. Thereby, this can be compensated in anticipation of a decrease in fuel pressure caused by fuel injection via the fuel injection valve 4. For this reason, the actual fuel pressure can be made to follow the target fuel pressure Pt more preferably.

  (4) In addition to the feedforward term, the operation voltage includes a feedback term for feedback control of the actual fuel pressure to the target fuel pressure Pt. Thereby, the actual fuel pressure can be suitably controlled by the target fuel pressure Pt.

  (5) The detected differential pressure Pf is feedback-controlled to the target differential pressure DF using the fuel pressure sensor 28 that detects the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure. The target fuel pressure Pt was calculated by adding the intake pressure Pm to the target differential pressure DF. Thereby, the detected differential pressure Pf can be directly used in feedback control. Further, since the target fuel pressure Pt is calculated by adding the intake pressure Pm to the detected differential pressure Pf, the target fuel pressure change amount ΔPt can be acquired based on this.

  (6) The internal combustion engine 1 is an intake port injection type internal combustion engine that is an internal combustion engine in which the fuel injection valve 4 injects fuel into the intake passage 2. For this reason, the fuel injection amount can be suitably controlled by controlling the target differential pressure DF to be substantially constant. In addition, in this case, the target fuel pressure Pt changes significantly due to the change in the intake pressure Pm, so that the control using the feedforward fuel supply amount Fp is particularly effective.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the required fuel amount ΔFp is calculated based on the intake pressure change amount ΔPm instead of the target fuel pressure change amount ΔPt. That is, the target fuel pressure Pt is basically a value obtained by adding a substantially constant target differential pressure DF to the intake pressure Pm. Therefore, the target fuel pressure change amount ΔPt is estimated approximately accurately based on the intake pressure change amount ΔPm. be able to.

  FIG. 7 shows a procedure of processing for controlling the fuel pressure in the delivery pipe 6 in the present embodiment to a target fuel pressure. The processing of FIG. 7 corresponds to the previous FIG. Note that the functional blocks of the present embodiment corresponding to the functional blocks shown in FIG. 2 are omitted.

  In this series of processes, first, in step S10a, the target differential pressure DF is map-calculated in the same manner as that shown in step S10 of FIG. In step S20a, an intake pressure change amount ΔPm is calculated. Specifically, the amount of change ΔPm in the intake pressure is calculated by subtracting the intake pressure Pm (i−1) detected last time from the intake pressure Pm (i) detected this time. In step S30a, the change amount ΔPm of the intake pressure is converted into a fuel amount ΔFp required to be supplied to the delivery pipe 6. In other words, the fuel amount ΔFp required to cause the pressure change in the delivery pipe 6 equal to the intake pressure change amount ΔPm is added. The proportionality coefficient K here is the same as that in step S30 shown in FIG.

  When the processing up to step S30a is completed in this way, the processing of steps S40 to S90 shown in FIG. 3 is performed, and this series of processing is once ended.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects according to the above (1) to (6) of the first embodiment.

  (7) The required fuel amount ΔFp is calculated based on the change amount ΔPm of the intake pressure. For this reason, the process which calculates target fuel pressure Pt can be omitted.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, as shown in FIG. 8, a fuel pressure sensor 38 that detects a differential pressure between the fuel pressure in the delivery pipe 6 and the atmospheric pressure is used.

  FIG. 9 shows a processing procedure for controlling the fuel pressure in the delivery pipe 6 to a target fuel pressure in the present embodiment. The process of FIG. 9 corresponds to the previous FIG. Note that the functional blocks of the present embodiment corresponding to the functional blocks shown in FIG. 2 are omitted.

  In the series of processing shown in FIG. 9, steps S10 to S50 of FIG. 3 are first performed. In subsequent step S60b, the fuel pressure PF is detected by the fuel pressure sensor 38. In step S70b, a feed forward voltage VP is calculated. This step S70b is a step corresponding to step S70 of FIG. However, in this embodiment, since the fuel pressure PF that is the differential pressure between the fuel pressure in the delivery pipe 6 and the atmospheric pressure is used, the map calculation is performed on the feedforward voltage Vp based on the fuel pressure PF and the feedforward fuel supply amount Fp. .

  In the subsequent step S80b, an operation voltage for feedback control is calculated so that the differential pressure between the fuel pressure Pf and the intake pressure Pm follows the target differential pressure DF. Again, this feedback control is PID control.

  In step S90, based on the feedforward voltage Vp calculated in step S70b and the feedback voltage Vpid calculated in step S80b, the final operation voltage Vt is calculated by the same process as in step S90 of FIG. .

  According to this embodiment described above, in addition to the effects (1) to (4) and (6) of the previous first embodiment, the following effects can be further obtained.

  (8) By using the fuel pressure sensor 38 that detects the differential pressure between the fuel pressure in the delivery pipe 6 and the atmospheric pressure, the detection value of the fuel pressure sensor 38 can be used directly when calculating the feedforward voltage Vp.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the second embodiment, the fuel pressure sensor 28 that detects the differential pressure between the fuel pressure in the delivery pipe 6 and the intake pressure is used, but the fuel pressure that detects the differential pressure between the fuel pressure in the delivery pipe 6 and the atmospheric pressure. A sensor 38 may be used. That is, the fuel pressure sensor 38 may be used for the process of calculating the operation voltage Vt based on the change amount of the intake pressure ΔPm.

  When calculating the feedforward voltage Vp based on the target fuel pressure change amount ΔPt or the intake pressure change amount ΔPm, the target fuel pressure Pt resulting from the change in the intake pressure Pm can be calculated without considering the fuel injection amount Finj. The fuel pressure in the delivery pipe 6 can be controlled in anticipation of an increase in deviation from the actual fuel pressure.

  -Feedback control is not limited to PID control. Further, even if feedback control is not performed, the operation amount is calculated based on the change amount ΔPt of the target fuel pressure or the change amount ΔPm of the intake pressure, so that the target fuel pressure Pt and the actual fuel pressure caused by the change of the intake pressure Pm are calculated. The fuel pressure in the delivery pipe 6 can be controlled in anticipation of an increase in the deviation.

  The method of calculating the required fuel amount ΔFp based on the target fuel pressure change amount ΔPt and the intake pressure change amount ΔPm is not limited to those exemplified in the above embodiments. That is, for example, when there is nonlinearity in the relationship between the amount of fuel supplied to the delivery pipe 6 and the amount of change in the fuel pressure in the delivery pipe 6, a conversion formula that takes this into account may be used.

  The parameters used for calculating the target differential pressure DF are not limited to the rotational speed of the internal combustion engine 1 and the intake pressure Pm. For example, one of these may be used, and the temperature of the cooling water of the internal combustion engine 1 may be further added to them. Further, in the configuration not including the intake pressure sensor 22, the intake pressure may be calculated from the detected value of the air flow meter or the detected value of the opening of the throttle valve. Further, for example, when a parameter other than the intake pressure is used as a parameter used when calculating the target fuel pressure Pt, among the parameters, a large change of the parameter leads to a large change in the target fuel pressure Pt. The operation voltage may be calculated.

  Further, the target differential pressure DF may be a fixed value.

  As a fuel supply device for an internal combustion engine that controls the actual fuel pressure in a pressure accumulating chamber that stores the fuel to a target fuel pressure in order to supply fuel of a predetermined pressure to the fuel injection valve, an intake port injection type internal combustion engine It is not limited to a fuel supply device. For example, in a direct-injection gasoline engine, even when control is performed to keep the differential pressure between the fuel pressure in the accumulator chamber and the pressure in the combustion chamber substantially constant, the amount of operation required for the above control based on the target amount of change in fuel pressure Setting is effective.

  -As a setting means to set the operation amount for controlling the actual fuel pressure to the target fuel pressure based on the target fuel pressure change amount and the predetermined parameter change amount when calculating the target fuel pressure, For example, dedicated hardware means may be used.

  In addition, the internal combustion engine 1 may be a single cylinder, and the actuator for controlling the fuel pressure in the pressure accumulating chamber is not limited to the fuel pump 10 having the above configuration. The amount of operation when operating this actuator is not limited to voltage.

The figure which shows the whole structure of 1st Embodiment which applied the fuel supply apparatus concerning this invention to the fuel supply apparatus of the internal combustion engine of an intake port injection type. The functional block diagram which controls the actual fuel pressure concerning the embodiment to the target fuel pressure. The flowchart which shows the procedure which controls the actual fuel pressure concerning the embodiment to the target fuel pressure. The time chart which shows transition of the control of the fuel pressure concerning the embodiment. The time chart which shows transition of the control of fuel pressure when not performing feedforward control based on the variation | change_quantity of target fuel pressure. The time chart which shows transition of the control of the fuel pressure by PID control. The flowchart which shows the procedure which controls the actual fuel pressure concerning 2nd Embodiment to the target fuel pressure. The figure which shows the whole structure of 3rd Embodiment. The flowchart which shows the procedure which controls the actual fuel pressure concerning 3rd Embodiment to the target fuel pressure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Intake passage, 4 ... Fuel injection valve, 6 ... Delivery pipe, 8 ... Fuel tank, 10 ... Fuel pump, 20 ... Electronic controller, 22 ... Intake pressure sensor, 28 ... Fuel pressure sensor

Claims (5)

In a fuel supply device for an internal combustion engine that controls the actual fuel pressure in a pressure accumulating chamber for storing fuel to a target fuel pressure in order to supply fuel at a predetermined pressure to a fuel injection valve,
Means for detecting a differential pressure between the fuel pressure in the pressure accumulating chamber and the intake pressure of the engine;
Means for feedback-controlling the detected differential pressure to a target differential pressure;
A feedforward operation amount for controlling the actual fuel pressure to the target fuel pressure calculated by adding intake air pressure to the target differential pressure is set based on a change amount of the target fuel pressure. A fuel supply device for an internal combustion engine, comprising: setting means. In a fuel supply device for an internal combustion engine that controls an actual fuel pressure in a pressure accumulating chamber for storing fuel to a target fuel pressure calculated based on a predetermined parameter in order to supply fuel at a predetermined pressure to a fuel injection valve.
Means for detecting a differential pressure between the fuel pressure in the pressure accumulating chamber and the intake pressure of the engine;
Means for feedback-controlling the detected differential pressure to a target differential pressure;
A fuel supply device for an internal combustion engine, comprising: setting means for setting a feedforward operation amount for controlling the actual fuel pressure to the target fuel pressure based on a change amount of the parameter. The fuel supply apparatus for an internal combustion engine according to claim 2, wherein the predetermined parameter is an intake pressure of the engine. The said setting means is provided with the means to convert the said variation | change_quantity into the fuel amount requested | required in the said pressure accumulation chamber, and the means to convert this converted fuel amount into the said operation amount in any one of Claims 1-3 A fuel supply device for an internal combustion engine as described. 5. The fuel supply device for an internal combustion engine according to claim 1, wherein the manipulated variable includes a feedforward term set based on a fuel amount injected through the fuel injection valve.

Images