JP3583673B2 - Fuel injection control device for in-cylinder injection engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel injection control device for a direct injection engine of a type in which high-pressure fuel is directly injected into each combustion chamber of a plurality of cylinders and burns by spark ignition, and in particular, the injection pulse width of the injector in accordance with the fuel pressure acting on the injector. The present invention relates to a fuel injection control device for an in-cylinder injection engine in which the reliability is improved by highly accurately correcting the fuel injection control.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a fuel injection control device for an in-cylinder injection engine in which an injector is arranged in a combustion chamber of each cylinder and fuel is directly injected into the combustion chamber is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-26046. Well known to be.
[0003]
The fuel injection control device described in the above publication detects the fuel pressure acting on the injector, controls the fuel pressure regulator so that the detected fuel pressure matches the target fuel pressure, and reduces the energization time (injection pulse width) of the injector. The correction is made based on the ratio between the detected fuel pressure and the reference fuel pressure.
[0004]
FIG. 13 is a block diagram schematically showing a fuel injection control device of a general direct injection engine.
In FIG. 13, an injector 1F is provided for each cylinder of the engine 1, and injects fuel directly into the combustion chamber of each cylinder.
[0005]
The engine 1 is provided with various sensors 2 for detecting an operating state and a fuel pressure sensor 12. The various sensors 2 include a known air flow sensor, a throttle sensor, a crank angle sensor, and the like.
[0006]
The driving information from the various sensors 2 and the detected fuel pressure PF from the fuel pressure sensor 12 are input to an electronic control unit (hereinafter referred to as “ECU”) 20.
The injector 1F has an electromagnetic solenoid driven by an injection pulse signal J from the ECU 20, and is driven to open by energizing the solenoid.
[0007]
The fuel supplied to the injector 1F is drawn from the fuel tank 3 and adjusted to the target fuel pressure PFo in the high-pressure pipe 8. As a result, fuel is injected from the injector 1F in an amount proportional to the pulse width (injection pulse width) of the injection pulse signal J.
[0008]
Intake air is distributed into each cylinder of the engine 1 via an intake pipe (not shown). An air filter, an air flow sensor, a throttle valve, a surge tank, and an intake manifold are arranged in the intake pipe in order from the upstream side.
[0009]
Fuel (gasoline or the like) in the fuel tank 3 is sucked by a low-pressure pump 4 driven by a motor 4M.
The low-pressure fuel discharged from the low-pressure pump 4 is supplied to a high-pressure pump 7 via a fuel filter 5 and a low-pressure pipe 6.
[0010]
The low-pressure pipe 6 branches into a low-pressure return pipe 6A in which a low-pressure regulator 9 is interposed, and is returned to the fuel tank.
The high-pressure pump 7 is driven by the engine 1, and the rotation speed of the high-pressure pump 7 corresponds to the engine speed.
[0011]
The high-pressure fuel discharged from the high-pressure pump 7 is supplied to the injector 1F via the high-pressure pipe 8.
The high-pressure pipe 8 branches into a high-pressure return pipe 8A in which a high-pressure regulator 10 is interposed, and a downstream side of the high-pressure return pipe 8A joins the low-pressure pipe 6 and the low-pressure return pipe 6A.
[0012]
The low-pressure regulator 9 adjusts the amount of fuel returning from the low-pressure return pipe 6A to the fuel tank 3. The fuel pressure supplied from the low-pressure pump 4 to the high-pressure pump 7 is adjusted to a predetermined low pressure by the return fuel amount by the low-pressure regulator 9.
[0013]
The high-pressure regulator 10 is driven by an excitation current Ri (control signal) supplied from the ECU 20, adjusts the amount of fuel returned to the low-pressure return pipe 6A, and changes the actual detected fuel pressure PF acting on the injector 1F to the target fuel pressure PFo. adjust.
[0014]
That is, the high-pressure regulator 10 continuously changes the opening area of the high-pressure return pipe 8A according to the exciting current Ri, and returns the fuel downstream of the high-pressure pump 7 to the low-pressure side.
The fuel pressure sensor 12 detects a fuel pressure PF in the high-pressure pipe 8.
[0015]
The ECU 20 captures not only the detected fuel pressure PF from the fuel pressure sensor 12 but also operating state information from the various sensors 2 and executes a predetermined calculation process to output a control signal calculated to various actuators.
[0016]
For example, the ECU 20 takes in the detected fuel pressure PF from the fuel pressure sensor 12 and performs the PID control according to the fuel pressure deviation ΔPF between the detected fuel pressure PF (or the average fuel pressure PFm) and the target fuel pressure PFo so that the detected fuel pressure PF becomes equal to the target fuel pressure PFo. A control signal (excitation current Ri) is output so as to match.
[0017]
FIG. 14 is a functional block diagram showing a main part of a conventional fuel injection control device for a direct injection engine, and corresponds to the configuration of the ECU 20 in FIG.
In FIG. 14, intake air amount detecting means 21, rotational speed detecting means 22, and fuel pressure detecting means 23 take in operating state information from various sensors 2 and fuel pressure sensor 12.
[0018]
The intake air amount detecting means 21 takes in the intake air amount Qa based on the detection signal of the air flow sensor, and the rotational speed detecting means 22 takes in the engine rotational speed Ne based on the crank angle signal from the crank angle sensor. Further, the fuel pressure detecting means 23 takes in the detected fuel pressure PF (the fuel pressure acting on the injector 1F) from the fuel pressure sensor 12 at a predetermined cycle.
[0019]
The injection amount calculating means 24 calculates a substantial effective pulse width Th by the injector 1F based on the intake air amount Qa and the engine speed Ne.
The injection amount correction means 25 corrects the effective pulse width Te based on the detected fuel pressure PF, and calculates the corrected effective pulse width Th.
[0020]
The invalid pulse width generation means 26 generates an invalid pulse width Td (constant value) corresponding to the operation time of the injector 1F at the reference fuel pressure PFb.
The adder 27 adds the corrected effective pulse width Th and the invalid pulse width Td, and outputs an injection pulse signal J having an injection pulse width TJ to the injector 1F.
[0021]
The injection amount calculating unit 24, the injection amount correcting unit 25, the invalid pulse width generating unit 26, and the adder 27 constitute an injection pulse calculating unit that outputs an injection pulse signal J to the injector 1F, and based on the detected fuel pressure PF. The injection pulse width TJ of the injector 1F is calculated.
[0022]
The fuel pressure control means 28 calculates a target fuel pressure PFo according to the operating state, performs fuel pressure feedback control so that the detected fuel pressure PF becomes the target fuel pressure PFo, and outputs an excitation current Ri to the high-pressure regulator 10.
[0023]
The injection amount calculation means 24 includes dividers 41, 43 and 44 and a multiplier 42.
The divider 41 divides the intake air amount Qa of the engine 1 by the engine speed Ne to calculate the actual intake air amount A / N charged into the combustion chamber in one intake stroke.
[0024]
The multiplier 42 calculates a corrected intake air amount K · A / N by multiplying the actual intake air amount A / N by a constant K.
The divider 43 calculates the fuel injection amount Qf by dividing the corrected intake air amount K · A / N by the target air-fuel ratio A / Fo.
[0025]
The divider 44 divides the fuel injection amount Qf by a basic flow rate gain Gi (fuel injection amount per unit injection pulse width at the reference fuel pressure PFb) of the injector 1F to obtain an effective pulse width Te (= Qf / Gi) is calculated.
[0026]
The injection amount correction means 25 includes a divider 51, a correction table 52, and a multiplier 53.
The divider 51 calculates a fuel pressure ratio Kp (= PF / PFb) between the detected fuel pressure PF and the reference fuel pressure PFb.
[0027]
The fuel pressure ratio Kp becomes a value larger than 1 when the detected fuel pressure PF rises above the reference fuel pressure PFb, and becomes a value smaller than 1 when the detected fuel pressure PF decreases below the reference fuel pressure PFb.
[0028]
The correction table 52 calculates a correction coefficient Kh (inversely proportional to the fuel pressure ratio Kp) corresponding to the value of the fuel pressure ratio Kp by searching a map.
The multiplier 53 multiplies the effective pulse width Te obtained by the injection amount calculating means 24 by the correction coefficient Kh, and calculates the corrected effective pulse width Th according to the detected fuel pressure PF.
[0029]
The fuel pressure control means 28 includes a target fuel pressure calculation means 81, a subtractor 82, and a PID control means 83.
The target fuel pressure calculating means 81 obtains a target fuel pressure PFo according to the operating state by map calculation.
[0030]
The subtractor 82 calculates a fuel pressure deviation ΔPF (= PF−PFo) between the detected fuel pressure PF and the target fuel pressure PFo.
The PID control means 83 performs a fuel pressure feedback control to make the detected fuel pressure PF coincide with the target fuel pressure PFo by PID control based on the fuel pressure deviation ΔPF, and generates an exciting current Ri for the high-pressure regulator 10 (fuel pressure regulator).
[0031]
Next, the calculation and correction operation of the injection pulse width TJ by the conventional fuel injection control device for a direct injection engine will be described with reference to FIGS.
[0032]
First, the intake air amount detecting means 21 in the ECU 20 takes in the intake air amount Qa measured by the air flow sensor, and the rotational speed detecting means 22 detects the engine rotational speed Ne from the crank angle signal, and outputs information indicating the operating state. Is input to the injection amount calculating means 24.
[0033]
Further, the fuel pressure detecting means 23 takes in the detected fuel pressure PF from the fuel pressure sensor 12 and inputs it to the injection amount correcting means 25 and the fuel pressure control means 28.
[0034]
The injection amount calculation means 24 calculates a corrected intake air amount K · A / N by multiplying the actual intake air amount A / N obtained by dividing the intake air amount Qa by the engine speed Ne by a constant K, and further calculates a corrected intake air amount K · A / N. The effective pulse width Te is calculated by dividing the fuel injection amount Qf obtained by dividing A / N by the target air-fuel ratio A / Fo by the flow rate gain Gi.
[0035]
The injection amount correcting means 25 searches the correction coefficient Kh from the fuel pressure ratio Kp between the detected fuel pressure PF and the reference fuel pressure PFb, and calculates the corrected effective pulse width Th by multiplying the effective pulse width Te by the correction coefficient Kh. .
[0036]
For example, when the detected fuel pressure PF is higher than the reference fuel pressure PFb, the injection amount per unit time increases. Therefore, the effective pulse width Th is reduced and corrected by multiplying by the correction coefficient Kh smaller than 1.
[0037]
An adder 27 associated with the injection amount calculation means 24 and the injection amount correction means 25 adds the invalid pulse width Td to the corrected effective pulse width Th to generate a final injection pulse signal J having the injection pulse width TJ. Generate and drive the injector 1F.
[0038]
On the other hand, the fuel pressure control means 28 performs PID control based on the fuel pressure deviation ΔPF between the detected fuel pressure PF and the target fuel pressure PFo, and controls the high-pressure regulator 10 with the exciting current Ri corresponding to the fuel pressure deviation ΔPF, thereby reducing the detected fuel pressure PF. The fuel pressure is made to coincide with the target fuel pressure PFo. Thus, the fuel pressure acting on injector 1F is controlled to a desired target fuel pressure PFo.
[0039]
When the fuel pressure (detected fuel pressure PF) acting on the injector 1F changes due to disturbance due to the correction of the injection pulse signal J, or when the ECU 20 changes the target fuel pressure PFo, the effective pulse width Th according to the fuel pressure ratio Kp. Can be optimized.
[0040]
By the way, in FIG. 14, the invalid pulse width generation means 26 sets the invalid pulse width Td to a constant value. However, since the invalid pulse width Td actually has a change characteristic corresponding to the detected fuel pressure PF, The injection pulse signal J does not always have an accurate injection pulse width TJ corresponding to the detected fuel pressure PF.
[0041]
FIG. 15 is a characteristic diagram showing the flow rate characteristics of the injector 1F according to the difference in the actual fuel pressure (detected fuel pressure PF). The horizontal axis represents the injection pulse width TJ [msec], and the vertical axis represents the fuel injection amount Qf [mcc]. is there.
[0042]
In FIG. 15, the dashed line indicates the flow rate characteristics when the detected fuel pressure PF is equal to the reference fuel pressure PFb, the broken line indicates the actual flow rate characteristics when the detected fuel pressure PF is higher than the reference fuel pressure PFb, and the solid line indicates the detected fuel pressure PF is higher than the reference fuel pressure PFb. Is a flow rate characteristic when a constant invalid pulse width Td is used in a case where is larger than the threshold value.
[0043]
When the detected fuel pressure PF is equal to the reference fuel pressure PFb, the slope of the flow rate characteristic (dotted line) corresponds to the flow rate gain Gi [mcc / msec] at the reference fuel pressure PFb, and when the detected fuel pressure PF is larger than the reference fuel pressure PFb. The slope of the flow characteristic (broken line or solid line) corresponds to a value (= Gi × Kp) obtained by multiplying the flow gain Gi by the fuel pressure ratio Kp.
[0044]
Further, in the reference fuel pressure PFb (dashed line), the effective pulse width Th1 added to the invalid pulse width Td corresponds to the effective pulse width Te before correction, and in the detected fuel pressure PF (solid line) larger than the reference fuel pressure PFb, The effective pulse width Th2 added to the invalid pulse width Td corresponds to a value obtained by multiplying the effective pulse width Te by the correction coefficient Kh (<1).
[0045]
In FIG. 15, when the detected fuel pressure PF is the reference fuel pressure PFb when the fuel injection amount Qf is to be injected, the pulse width TJ of the injection pulse signal J has a gradient due to the characteristic of the flow rate gain Gi (dashed line). It is the sum of the effective pulse width Th1 (= Te) and the invalid pulse width Td.
[0046]
If the detected fuel pressure PF is larger than the reference fuel pressure PFb, the pulse width TJ of the injection pulse signal J is the sum of the effective pulse width Th2 and the invalid pulse width Td due to the characteristic of the flow rate gain Gi × Kp (solid line). .
[0047]
In FIG. 14, when an attempt is made to inject the fuel injection amount Qf, first, the divider 44 in the injection amount calculating means 24 divides the fuel injection amount Qf by the flow rate gain Gi at the reference fuel pressure PFb to obtain the reference fuel pressure PFb. , The effective pulse width Te (= Th1) is calculated.
[0048]
Next, the injection amount correction means 25 obtains a correction coefficient Kh from the fuel pressure ratio Kp between the detected fuel pressure PF and the reference fuel pressure PFb by using the correction table 52, and multiplies the effective pulse width Te by the correction coefficient Kh. Of the effective pulse width Th (= Th2).
[0049]
At this time, if the detected fuel pressure PF is equal to the reference fuel pressure PFb, the fuel pressure ratio Kp is 1, and therefore the correction coefficient Kh is also 1. Therefore, the effective pulse width Th calculated by the multiplier 53 is Th1 = Te × Kh (= Te).
[0050]
Finally, the adder 27 adds the invalid pulse width Td to the effective pulse width Th1, and outputs an ejection pulse signal J having a final ejection pulse width TJ (= Th1 + Td).
[0051]
On the other hand, if the detected fuel pressure PF is higher than the reference fuel pressure PFb, the fuel pressure ratio Kp becomes larger than 1, so the correction coefficient Kh becomes a value smaller than 1, and the effective pulse width Th becomes Th2 = Th1 × Kh (<Te ).
[0052]
At this time, the adder 27 calculates the final ejection pulse width TJ (= Th2 + Td) by adding the invalid pulse width Td to the effective pulse width Th2.
However, according to the actual flow rate characteristic (broken line), since the invalid pulse width Td is different, the actually required injection pulse width TJ is longer than the calculated value (= Th2 + Td).
[0053]
Because the injector 1F opens by overcoming the fuel pressure that actually acts, when the actual fuel pressure (detected fuel pressure PF) becomes higher than the reference fuel pressure PFb, the injector 1F is supplied with the injection pulse signal J and then actually opened. This is because the dead time (invalid pulse width Td) until the valve operation starts is increased.
[0054]
As described above, when the injection pulse width TJ (= Th2 + Td) is corrected by the flow rate characteristic (solid line) in FIG. 15, the time for actually injecting the fuel becomes longer than the originally required time (the injection pulse width based on the flow rate characteristic indicated by the broken line). Will also be shorter.
[0055]
Particularly, in the injector 1F of the direct injection engine that injects fuel directly into the combustion chamber, the fuel pressure acting on the injector 1F is higher than that of the general engine having the injector in the intake manifold because of the restriction on the injection period. Thus, the flow rate gain Gi of the injector 1F is set to a large value so that the required fuel amount can be injected in a short period of time. Therefore, a change in the dead time can be a considerable difference in the injection amount.
[0056]
[Problems to be solved by the invention]
As described above, the fuel injection control device of the conventional in-cylinder injection engine does not take into account the flow characteristic (see the broken line in FIG. 15) that the invalid pulse width Td also changes due to the change in the detected fuel pressure PF. There is a problem that an ejection pulse signal J having an accurate ejection pulse width TJ according to the PF cannot be obtained.
[0057]
In particular, since the injector 1F of the in-cylinder injection engine injects a required amount of fuel in a short period of time by the high pressure fuel pressure, even if it is a change in the invalid pulse width Td (dead time), a deviation of the injection amount that cannot be ignored is considered. There was a problem that occurred.
[0058]
The present invention has been made in order to solve the above problems, and corrects the injection pulse width by correcting the invalid pulse width according to the change in the detected fuel pressure, thereby improving the accuracy of the fuel injection amount. An object of the present invention is to obtain an improved fuel injection control device for a direct injection engine.
[0059]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a fuel injection control device for an in-cylinder injection engine, wherein various sensors for detecting an operating state of the engine, an injector for directly injecting fuel into a cylinder of the engine, and a fuel pressure acting on the injector are detected. Pressure control means for calculating the injection pulse width of the injector based on the fuel pressure detected by the fuel pressure detection means, the invalidation of the injector in accordance with the detected fuel pressure. Dead time correction means for correcting pulse widthAnd fuel pressure control means for controlling the fuel pressure acting on the injector to a target fuel pressure according to the operating state,The injection pulse calculation means adds the effective pulse width and the invalid pulse width according to the operation state to calculate the injection pulse width.The dead time correction means calculates the invalid pulse width based on the target fuel pressure when the fuel pressure deviation between the detected fuel pressure and the target fuel pressure is within a predetermined value, and when the fuel pressure deviation exceeds the predetermined value, Corrects invalid pulse width based on detected fuel pressureThings.
[0061]
In addition, the present inventionClaim 2The fuel injection control device for a direct injection engine according toClaim 1The dead time correction means corrects the invalid pulse width based on the detected fuel pressure only when the fuel pressure deviation continuously exceeds a predetermined value for a predetermined time or more, and based on the target fuel pressure when the condition is not satisfied. In this case, the invalid pulse width is corrected.
[0062]
In addition, the present inventionClaim 3The fuel injection control device for a direct injection engine according toClaim 1In the above, the injection pulse calculating means corrects the effective pulse width based on the target fuel pressure when the fuel pressure deviation is within a predetermined value, and when the fuel pressure deviation exceeds the predetermined value, the effective pulse based on the detected fuel pressure. This is to correct the width.
[0063]
In addition, the present inventionClaim 4The fuel injection control device for a direct injection engine according toClaims 1 to 3One of1 itemIn, the predetermined value is changed according to the target fuel pressure.
[0064]
In addition, the present inventionClaim 5The fuel injection control device for a direct injection engine according toClaims 1 to 4One of1 itemIn the above, the predetermined value is set to a value equal to or higher than a pulsation component constantly superimposed on the detected fuel pressure.
[0065]
In addition, the present inventionClaim 6The fuel injection control device for a direct injection engine according toClaims 1 to 5One ofIn one sectionIn this case, a failure determining means for determining a failure of the fuel pressure detecting means is provided, and the dead time correcting means corrects the injection pulse width based on the target fuel pressure when the failure of the fuel pressure detecting means is determined.
[0066]
In addition, the present inventionClaim 7The fuel injection control device for a direct injection engine according toVarious sensors for detecting the operating state of the engine, an injector for directly injecting fuel into the cylinder of the engine, a fuel pressure detecting means for detecting the fuel pressure acting on the injector, and an injection pulse of the injector based on the fuel pressure detected by the fuel pressure detecting means. In a fuel injection control device for a direct injection engine having an injection pulse calculating means for calculating a width, a dead time correcting means for correcting an invalid pulse width of an injector according to a detected fuel pressure;Mean fuel pressure calculating means for calculating mean fuel pressure from detected fuel pressureIs provided, the injection pulse calculating means calculates the injection pulse width by adding the effective pulse width and the invalid pulse width according to the operation state,The dead time correction means corrects the invalid pulse width based on the average fuel pressure when the fuel pressure deviation between the detected fuel pressure and the average fuel pressure is within a predetermined value, and detects the detected fuel pressure when the fuel pressure deviation exceeds the predetermined value. The invalid pulse width is corrected based on the following.
[0067]
In addition, the present inventionClaim 8The fuel injection control device for a direct injection engine according toClaim 7The dead time correction means corrects the invalid pulse width based on the detected fuel pressure only when the fuel pressure deviation continuously exceeds a predetermined value for a predetermined time or more, and based on the average fuel pressure when the condition is not satisfied. In this case, the invalid pulse width is corrected.
[0068]
In addition, the present inventionClaim 9The fuel injection control device for a direct injection engine according toClaim 7In the above, the injection pulse calculating means corrects the effective pulse width based on the average fuel pressure when the fuel pressure deviation is within a predetermined value, and when the fuel pressure deviation exceeds the predetermined value, the effective pulse width based on the detected fuel pressure. This is to correct the width.
[0069]
In addition, the present inventionClaim 10The fuel injection control device for a direct injection engine according toClaims 7 to 9One ofIn one sectionHere, the predetermined value is changed according to the average fuel pressure.
[0070]
In addition, the present inventionClaim 11The fuel injection control device for a direct injection engine according toClaims 1 to 10One ofIn one sectionHere, the predetermined value is changed according to the engine speed.
[0071]
In addition, the present inventionClaim 12The fuel injection control device for a direct injection engine according toClaims 1 to 11One ofIn one sectionHere, the predetermined value is changed according to the injection amount of the injector.
[0072]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
Note that the entire configuration and the configuration of the fuel supply system according to the first embodiment of the present invention are the same as those described above (see FIG. 13), and will not be described in detail here.
[0073]
FIG. 1 shows a first embodiment of the present invention.Of equipment related toFIG. 3 is a block diagram showing a main part, corresponding to the configuration of the ECU 20A.
In FIG. 1, the same components as those described above (see FIG. 14) are denoted by the same reference numerals, and detailed description thereof is omitted. Here, the same injection amount correction unit 25 as described above is used, but an injection amount correction unit having another configuration such as omitting the divider 51 may be used.
[0074]
In this case, a dead time correction unit 29 having a dead time correction table 91 is provided between the fuel pressure detection unit 23 and the adder 27.
The dead time correction unit 29 uses the dead time correction table 91 to search and calculate an invalid pulse width TD corresponding to the detected fuel pressure PF, and generates a corrected invalid pulse width TD.
[0075]
Therefore, the adder 27 in the injection pulse calculating means adds the effective pulse width Th calculated in accordance with the operation state and the corrected invalid pulse width TD to obtain the final pulse width TJ of the injection pulse signal J. Is operated to drive the injector 1F.
[0076]
Next, referring to FIG. 2, FIG.apparatusThe relationship between the flow characteristics of the injector 1F and the corrected injection pulse width will be described.
[0077]
In FIG. 2, the one-dot chain line shows the flow rate characteristics at the reference fuel pressure PFb as in the above (see FIG. 15), and the solid line shows the detected fuel pressure PF (> PFb).The device of FIG.It is a flow rate characteristic according to FIG. A broken line indicates a flow rate characteristic when the above-described invalid pulse width Td is used.
[0078]
First, similarly to the above, the injection amount calculating means 24 in FIG. 1 calculates the effective pulse width Te at the reference fuel pressure PFb, and the injection amount correcting means 25 converts the correction coefficient Kh obtained from the correction table 52 into the effective pulse width. The corrected effective pulse width Th is calculated by multiplying the width Te.
[0079]
Further, the dead time correction unit 29 searches the invalid pulse width TD corresponding to the detected fuel pressure PF using the dead time correction table 91, and the adder 27 adds the invalid pulse width TD to the valid pulse width Th. The final injection pulse width TJ is calculated.
[0080]
At this time, the injection pulse width TJ (= TD + Th2) at the detected fuel pressure PF larger than the reference fuel pressure PFb matches the injection pulse width necessary for injecting the fuel injection amount Qf due to the flow characteristics indicated by the solid line in FIG. I do.
[0081]
Next, referring to the flowchart of FIG.The device of FIG.The correction processing of the ejection pulse signal J by the above will be specifically described.
3, first, the injection amount calculation means 24 reads the intake air amount Qa (step S101) and reads the engine speed Ne (step S102). Further, the injection amount correction means 25 reads the detected fuel pressure PF (step S103).
[0082]
The injection amount calculating means 24 multiplies a value obtained by dividing the intake air amount Qa by the engine speed Ne (actual intake air amount A / N) by a constant K, and calculates a corrected intake air amount K * to be charged into the combustion chamber per intake stroke. A / N is calculated (step S104).
[0083]
Subsequently, the fuel injection amount Qf is calculated by dividing the corrected intake air amount K · A / N by the target air-fuel ratio A / Fo (step S105), and the fuel injection amount Qf is divided by the flow rate gain Gi of the injector to obtain an effective pulse. The width Te is calculated (Step S106).
[0084]
Further, the injection amount correcting means 25 obtains the fuel pressure ratio Kp between the detected fuel pressure PF and the reference fuel pressure PFb (step S107), and searches the correction coefficient Kh corresponding to the value of Kp using the correction table 52 (step S108). Then, the corrected effective pulse width Th is calculated by multiplying the effective pulse width Te by the correction coefficient Kh (step S109).
[0085]
Further, the dead time correction unit 29 searches the invalid pulse width TD at the detected fuel pressure PF using the dead time correction table 91 (step S110).
Finally, the adder 27 obtains the final injection pulse width TJ by adding the corrected effective pulse width Th and the searched and calculated invalid pulse width TD (step S111), and executes the processing routine of FIG. Get out.
[0086]
Thus, by providing the dead time correction means 29 and correcting the invalid pulse width TD of the injector 1F according to the detected fuel pressure PF, the invalid pulse width TD is appropriately corrected according to the fuel pressure acting on the injector 1F. Therefore, even when the fuel pressure changes, the accuracy of the fuel injection amount Qf can be improved.
[0087]
The device shown in FIG.In the above, the injection pulse signal J was corrected using the detected fuel pressure PF in order to maintain the responsiveness at the time of the fuel pressure transition. However, the actual detected fuel pressure PF includes the discharge pulsation component of the high-pressure pump 7 driven by the engine 1. Are constantly superimposed.
[0088]
Therefore, if the invalid pulse width TD (injection pulse width TJ) is to be precisely corrected in accordance with the detected fuel pressure PF even for a steady pulsation component, the injection pulse width TJ is set to the target value at the actual injection fuel pressure. Therefore, the air-fuel ratio A / F may vary.
[0089]
Therefore, in order to stabilize the injection pulse width TJ at the time of steady fuel pressure, when the variation of the detected fuel pressure PF is equal to or less than the pulsating component (at steady state), the target fuel pressure PFo is used without using the detected fuel pressure PF. The injection pulse signal J may be corrected.
[0090]
Hereinafter, referring to FIGS. 4 and 5, according to the present invention, the fuel pressure information for correction calculation is switched in accordance with the fluctuation state of the detected fuel pressure PF.Embodiment 1Will be described.
[0091]
In this case, the dead time correction means 29 takes in the target fuel pressure PFo and the fuel pressure deviation ΔPF from the fuel pressure control means 28, and compares the fuel pressure deviation ΔPF with a predetermined value with a comparison means (not shown). Switching means for switching the fuel pressure information input to the dead time correction table 91 from the detected fuel pressure PF to the target fuel pressure PFo.
[0092]
That is, the dead time correction means 29 corrects the invalid pulse width TD using the detected fuel pressure PF when the fuel pressure deviation ΔPF is larger than a predetermined value (comparison reference). Corrects the invalid pulse width TD using the target fuel pressure PFo.
The predetermined value is set to a value equal to or higher than a pulsation component that is constantly superimposed on the detected fuel pressure PF.
[0093]
FIG. 4 is a timing chart showing the behavior of the detected fuel pressure PF (actual fuel pressure). The solid line indicates the time change of the detected fuel pressure PF, and the broken line indicates the time change of the target fuel pressure PFo.
In FIG. 4, Z1, Z3, Z5 and Z7 are normal sections without disturbance, Z2 and Z6 are fuel pressure fluctuation sections due to disturbance, and Z4 is a fuel pressure fluctuation section when the target fuel pressure PFo is switched. .
[0094]
Normally, the fuel pressure (detected fuel pressure PF) acting on the injector 1F steadily includes a pulsation width ΔPFe of the degree shown in each of the sections Z1, Z3, Z5 and Z7 in FIG.
[0095]
Therefore, the comparison means in the dead time correction means 29 sets a predetermined value D (≧ △ PFe) for determining the state of the fuel pressure deviation ΔPF (= PF−PFo), and the change state of the detected fuel pressure PF is steady. It is determined whether or not the pulsation state (see the sections Z1, Z3, Z5, Z7).
[0096]
If the fuel pressure deviation ΔPF is equal to or less than a predetermined value D (steady pulsating state), the stabilization of the steady-state injection pulse width TJ is realized by performing the dead time correction using the stable target fuel pressure PFo. Can be.
[0097]
When the fuel pressure deviation ΔPF exceeds the predetermined value D as shown in each of the sections Z2, Z4, and Z6, the fuel pressure correction or the dead time correction is performed using the detected fuel pressure PF, thereby improving the responsiveness during the fuel pressure transition. Can be maintained.
[0098]
FIG.Embodiment 16 is a flowchart showing a process for correcting a dead time (injection pulse width) according to the first embodiment.
Here, it is assumed that the injection amount correction means 25 and the dead time correction means 29 read not only the detected fuel pressure PF but also the target fuel pressure PFo and the fuel pressure deviation ΔPF as the fuel pressure information.
[0099]
5, first, the injection amount correction means 25 and the dead time correction means 29 in the ECU 20A read the detected fuel pressure PF (step S201), and read the target fuel pressure PFo and the fuel pressure deviation ΔPF from the fuel pressure control means.
[0100]
Subsequently, the absolute value △ PFa (= | PF−PFo |) of the fuel pressure deviation ΔPF between the detected fuel pressure PF and the target fuel pressure PFo is obtained (Step S202), and is compared with a predetermined value D to determine the fuel pressure deviation absolute value ΔPFa. It is determined whether the value is equal to or less than the value D (step S203).
[0101]
If it is determined that D ≧ す な わ ち PFa (that is, YES), the detected fuel pressure PF is in a steady state change state, and the injection amount correction means 25 and the dead time correction means 29 use the detected fuel pressure PF for calculation. Instead, the arithmetic processing is performed by replacing the detected fuel pressure PF with the target fuel pressure PFo.
[0102]
That is, the injection amount correction means 25 calculates the fuel pressure ratio Kp as shown in the following equation (1) using the target fuel pressure PFo (step S204), and uses the fuel pressure ratio Kp based on the target fuel pressure PFo as the correction table 52. Search for.
[0103]
Kp = PFo / PFb (1)
[0104]
Further, the dead time correction means 29 searches the dead time correction table 91 using the target fuel pressure PFo, obtains the invalid pulse width TD from the function f (PFo) of the target fuel pressure PFo (step S205), and performs the processing in FIG. Exit the routine.
[0105]
On the other hand, if it is determined in step S203 that D <ＮＯPFa (that is, NO), it means that the detected fuel pressure PF (or the target fuel pressure PFo) has greatly changed, and therefore, the calculation using the detected fuel pressure PF is executed.
[0106]
That is, the injection amount correction means 25 calculates the fuel pressure ratio Kp using the detected fuel pressure PF as in the following equation (2) (step S206), and uses the fuel pressure ratio Kp based on the detected fuel pressure PF to correct the correction table 52. Search for.
[0107]
Kp = PF / PFb (2)
[0108]
Further, the dead time correction means 29 searches the dead time correction table 91 using the detected fuel pressure PF, finds the invalid pulse width TD from the function f (PF) of the detected fuel pressure PF (step S207), and executes the processing routine of FIG. Get out of.
[0109]
As described above, the processing is switched between the processing in steps S204 and S205 and the processing in steps S206 and S207 according to the fuel pressure deviation ΔPF.
That is, when the fuel pressure deviation ΔPF is small (D ≧ ΔPF) (sections Z1, Z3, Z5, Z7), the correction of the injection pulse signal J based on the target fuel pressure PFo is executed.
[0110]
At this time, since the predetermined value D is set to be equal to or larger than the fuel pressure pulsation width ΔPFe, in a steady operation state, the injection pulse width TJ can be corrected without being affected by the fuel pressure pulsation width ΔPFe, Therefore, variation in the air-fuel ratio A / F can be suppressed.
[0111]
On the other hand, when a large fuel pressure fluctuation (D <ΔPF) occurs due to disturbance or the like (sections Z2 and Z6), or when the target fuel pressure PFo is switched and the detected fuel pressure PF changes (section Z4), the detection is performed. The correction of the injection pulse signal J based on the fuel pressure PF is executed.
[0112]
Therefore, when the fuel pressure acting on the injector 1F changes due to a disturbance or the target fuel pressure PFo is changed by the fuel pressure control means 28, the injection pulse width TJ can be corrected with good responsiveness based on the detected fuel pressure PF. it can.
[0113]
Here, the fuel pressure information is switched not only in the dead time correcting means 29 but also in the injection amount correcting means 25. However, only the dead time correcting means 29 performs switching of the fuel pressure information according to the fuel pressure deviation ΔPF. Is also good.
[0114]
Embodiment 2 FIG.
The aboveEmbodiment 1In the above, when the fuel pressure deviation ΔPF exceeds the predetermined value D, the detected fuel pressure PF is used immediately for the correction calculation of the injection pulse signal J. However, redundancy may be provided in consideration of the duration of the state where D <ΔPF is satisfied. Good.
[0115]
Hereinafter, the correction calculation based on the detected fuel pressure PF is executed only when the fuel pressure deviation ΔPF exceeds the predetermined value D continuously for a predetermined time or more.Embodiment 2Will be described with reference to FIG.
[0116]
FIG.Embodiment 26 is a flowchart showing a process for correcting a dead time (injection pulse width) according to the first embodiment.
In FIG. 6, steps S201 to S207 are the same processing steps as described above (see FIG. 5), and a detailed description thereof will be omitted.
[0117]
Also, it is assumed that the time measurement counter CNT used in the added steps S301 to S303 has been cleared to 0 in advance by initial processing (not shown).
[0118]
First, in steps S201 to S203 similar to the above, the absolute value △ PFa of the fuel pressure deviation is obtained and compared with a predetermined value D.
If it is determined that D ≧ △ PFa (that is, YES), the time measurement counter CNT is cleared to 0 (step S301), and it is determined whether the value of the time measurement counter CNT is greater than 1 (step S301). S302).
[0119]
On the other hand, if it is determined in step S301 that D <△ PFa (that is, NO), the time measurement counter CNT is incremented (step S303), and the process proceeds to step S302.
[0120]
If it is determined in step S302 that CNT ≦ 1 (that is, NO), the fuel pressure deviation absolute value △ PFa exceeding the predetermined value D has not been detected, or even if it has been detected, it is within one time. The process proceeds to correction processing steps S204 and S205 using the fuel pressure PFo.
[0121]
On the other hand, if it is determined in step S302 that CNT> 1 (that is, YES), it is detected that the absolute value of the fuel pressure deviation ΔPFa exceeding the predetermined value D has occurred continuously at least twice (the predetermined time) or more. The process proceeds to steps S206 and S207 for correcting the fuel pressure PF.
[0122]
As described above, when the number of consecutive detections of the fuel pressure deviation ΔPFa exceeding the deviation determination value D is one or less, the correction based on the target fuel pressure PFO is executed, and the number of consecutive detections of the fuel pressure deviation ΔPFa exceeding the deviation determination value D becomes If it is twice or more (predetermined time) or more, the correction based on the detected fuel pressure PF is executed.
[0123]
That is, the injection amount correction means 25 corrects the effective pulse width Th based on the detected fuel pressure PF only when the fuel pressure deviation ΔPF exceeds the predetermined value D continuously for a predetermined time or more, and when the above condition is not satisfied. Corrects the effective pulse width Th based on the target fuel pressure PFo.
[0124]
The dead time correcting means 29 corrects the invalid pulse width TD based on the detected fuel pressure PF only when the fuel pressure deviation ΔPF continuously exceeds a predetermined value D for a predetermined time or more. Corrects the invalid pulse width TD based on the target fuel pressure PFo.
[0125]
As a result, even if the fuel pressure pulsation width ΔPFe exceeds the predetermined value D instantaneously due to a change in the operation state or occurrence of noise, the correction of the injection pulse width TJ based on the detected fuel pressure PF does not need to be performed, and the idle Variations in the fuel ratio A / F can be suppressed.
[0126]
Embodiment 3 FIG.
The aboveEmbodiments 1 and 2In the above, fuel pressure information for correcting the injection pulse signal J is switched to the detected fuel pressure PF or the target fuel pressure PFo in accordance with the fuel pressure deviation ΔPF between the detected fuel pressure PF and the target fuel pressure PFo. The fuel pressure information may be switched to the detected fuel pressure PF or the average fuel pressure PFm according to the fuel pressure deviation ΔPFm.
[0127]
Hereinafter, according to the present invention, the fuel pressure information is switched according to the fuel pressure deviation ΔPFm between the detected fuel pressure PF and the average fuel pressure PFm.Embodiment 3Will be described.
FIG.Embodiment 36 is a timing chart showing the behavior of a detected fuel pressure PF (actual fuel pressure) for explaining the operation according to FIG.
[0128]
In FIG. 7, a solid line indicates a time change of the detected fuel pressure PF, and a broken line indicates a time change of the average fuel pressure PFm. The same components as those described above (see FIG. 4) are denoted by the same reference numerals and detailed description thereof is omitted. .
In this case, the ECU 20A includes an average fuel pressure calculating means (not shown) for calculating the average fuel pressure PFm from the detected fuel pressure PF.
[0129]
When the fuel pressure deviation ΔPFm between the detected fuel pressure PF and the average fuel pressure PFm is within a predetermined value D, the dead time correction means 29 corrects the invalid pulse width TD based on the average fuel pressure PFm, and the fuel pressure deviation ΔPFm becomes a predetermined value. If the value D is exceeded, the invalid pulse width TD is corrected based on the detected fuel pressure PF.
[0130]
Therefore, as described above, in the steady-state sections Z1, Z3, Z5, and Z7, the variation in the air-fuel ratio A / F can be suppressed by using the stable average fuel pressure PFm for the correction calculation.
[0131]
In addition, in the sections Z2, Z4, and Z6 where the fuel pressure fluctuation is large, the response of the correction calculation can be improved by using the detected fuel pressure PF.
[0132]
Further, only when the fuel pressure deviation ΔPFm continuously exceeds the predetermined value D for a predetermined time or more, the correction calculation is performed based on the detected fuel pressure PF, and otherwise, the correction calculation is performed based on the average fuel pressure PFm. If this is the case, the effects of instantaneous fluctuations of the detected fuel pressure PF and noise can be eliminated.
[0133]
Further, if the predetermined value D is changed according to the magnitude of the average fuel pressure PFm (for example, the predetermined value D is corrected to increase as the average fuel pressure PFm increases), the fuel injection amount Qf is always accurately corrected according to the driving state. The calculation can be realized, and the reliability of the correction control of the injection pulse signal J can be further improved.
[0134]
Embodiment 4 FIG.
The aboveEmbodiments 1 and 2In the above, the predetermined value D as a criterion for determining the absolute value of the fuel pressure deviation ΔPFa is a fixed value. However, the predetermined value D may be changed according to the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf.
[0135]
In this case, the predetermined value D for switching the fuel pressure information for correcting the pulse width of the injection pulse signal J is set to an appropriate value according to at least one of the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf. Be changed.
[0136]
Next, according to the present invention, the predetermined value D is switched according to the operating state.Embodiment 4Will be described.
8 to 10 illustrate the present invention.Embodiment 4FIG. 4 is an explanatory diagram showing a change set value of the predetermined value D according to the above. In each figure, a solid line is a characteristic curve of the fuel pressure pulsation width ΔPFe, and a dashed line is a characteristic curve of the predetermined value D.
[0137]
8 shows changes in the fuel pressure pulsation width ΔPFe and the predetermined value D with respect to the target fuel pressure PFo, FIG. 9 shows changes in the fuel pressure pulsation width ΔPFe and the predetermined value D with respect to the engine speed Ne, and FIG. 10 shows the fuel pressure with respect to the fuel injection amount Qf. The pulsation width ΔPFe and the change of the predetermined value D are shown.
[0138]
As shown by the solid lines in FIGS. 8 to 10, the characteristics of the fuel pressure pulsation width ΔPFe with respect to the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf are eigenvalues that can be determined to some extent by the structures of the high-pressure pump 7 and the high-pressure regulator 10. is there.
[0139]
Therefore, if the characteristic of the appropriate predetermined value D corresponding to the fuel pressure pulsation width ΔPFe is set in advance as shown by the one-dot chain line in FIGS. 8 to 10, the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount The fuel pressure information can be appropriately switched regardless of the change in Qf.
[0140]
Next, referring to the flowchart of FIG.Embodiment 4Will be described with reference to FIG.
In FIG. 11, first, the injection amount correction unit 25 and the dead time correction unit 29 read the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf, respectively (steps S401, S402, S403).
[0141]
Subsequently, a predetermined value D for the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf is searched in a table according to the characteristic curves of FIGS. 8 to 10, and a value indicating the maximum value is finally determined. The selected value is selected and set as a predetermined value D serving as an appropriate criterion (step S404), and the process exits from the processing routine of FIG.
[0142]
Hereinafter, the above-described correction processing is performed using an appropriate predetermined value D corresponding to the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf.
[0143]
In this way, by changing the reference (predetermined value D) for the absolute value of the fuel pressure deviation ΔPFa according to the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf, the target fuel pressure PFo, the engine speed Ne, and the fuel Even if the fuel pressure pulsation width ΔPFe changes due to a change in the injection amount Qf, the injection pulse width TJ can be corrected without being affected by the fuel pressure pulsation width ΔPFe, so that the air-fuel ratio A / F variation can be suppressed. .
[0144]
In FIG. 10, the fuel injection amount Qf is used as the engine load information, and the predetermined value D is changed based on the fuel injection amount Qf. However, the present invention is not particularly limited to the fuel injection amount Qf and corresponds to the engine load. Other information may be used as long as it is a parameter to be performed.
[0145]
Further, as shown in FIGS. 8 to 10, the target fuel pressure PFo, the engine speed Ne, and the fuel injection amount Qf are treated as separate parameters, and the characteristic curves of the predetermined values D are set for each of them, but are not treated as separate parameters. Even if the predetermined value D is determined using a function obtained by combining all parameters as an index, it goes without saying that the same operation and effect can be obtained.
[0146]
Embodiment 5 FIG.
The aboveEmbodiments 1 and 2Does not consider the correction calculation when the fuel pressure detecting means 23 has failed, but when the fuel pressure detecting means 23 fails, the injection pulse signal J (the fuel injection amount Qf) is based on the abnormal detected fuel pressure PF. After correction, the fuel injection amount Qf may greatly deviate from the target value, and a misfire may occur.
[0147]
Therefore, when the fuel pressure detecting means 23 fails, it is desirable to correct the injection pulse width TJ based on the target fuel pressure PFo of the fuel pressure control means 28 without using the detected fuel pressure PF.
[0148]
In the following, according to the present invention, when the fuel pressure detecting means 23 fails, the correction calculation is performed using the target fuel pressure PFo.Embodiment 5Will be described.
In this case, the ECU 20A includes a failure determination unit (not shown) for determining a failure of the fuel pressure detection unit 23.
[0149]
The dead time correcting means 29 is configured to correct the injection pulse width TJ based on the target fuel pressure PFo when the failure of the fuel pressure detecting means 23 is determined.
[0150]
Next, referring to the flowchart of FIG.Embodiment 5The switching operation of the fuel pressure information according to the above will be described.
In FIG. 12, first, the failure determination unit determines whether the fuel pressure detection unit 23 (fuel pressure sensor) is out of order (step S501).
[0151]
Note that the failure determination means may be constituted by known means, for example, by outputting a failure determination signal when a detected fuel pressure PF deviating from the allowable range is generated, and will not be described in detail.
[0152]
If it is determined in step S501 that the fuel pressure detecting means 23 is malfunctioning (that is, YES), the target fuel pressure PFo is set as the detected fuel pressure PF (fuel pressure information) (step S502), and the process exits from the processing routine of FIG.
[0153]
On the other hand, if it is determined in step S501 that the fuel pressure detecting means 23 is not malfunctioning (that is, NO), the fuel pressure detecting means 23 is normal, and the process exits from the processing routine of FIG. 12 without executing the processing of step S502.
Hereinafter, the correction calculation of the injection pulse signal J is performed according to the above-described processing.
[0154]
As described above, when the fuel pressure detecting means 23 fails, the injection pulse width TJ is corrected based on the target fuel pressure PFo, so that the injection pulse width TJ is not corrected at the abnormal detected fuel pressure PF, and high accuracy is achieved. The injection pulse width TJ can be secured, and occurrence of misfire or the like can be suppressed.
[0155]
Embodiment 6 FIG.
The aboveIn each embodiment, for example, FIG.As described above, the case where the fuel pressure of the high-pressure regulator 10 is feedback-controlled by the fuel-pressure control means 28 has been described. However, instead of the high-pressure regulator 10, a mechanical fuel-pressure regulator that does not perform the fuel-pressure feedback control may be used.
[0156]
【The invention's effect】
As described above, according to the first aspect of the present invention, various sensors for detecting the operating state of the engine, the injector for directly injecting fuel into the cylinder of the engine, and the fuel pressure detecting means for detecting the fuel pressure acting on the injector Correcting the invalid pulse width of the injector according to the detected fuel pressure in a fuel injection control device for a direct injection engine, comprising: an injection pulse calculating means for calculating an injection pulse width of the injector based on the fuel pressure detected by the fuel pressure detecting means. Waste time correction meansAnd fuel pressure control means for controlling the fuel pressure acting on the injector to a target fuel pressure according to the operating state,The injection pulse calculation means adds the effective pulse width and the invalid pulse width according to the operation state to calculate the injection pulse width.The dead time correction means calculates the invalid pulse width based on the target fuel pressure when the fuel pressure deviation between the detected fuel pressure and the target fuel pressure is within a predetermined value, and when the fuel pressure deviation exceeds the predetermined value, Corrects invalid pulse width based on detected fuel pressureTo correct the injection pulse width.Stabilizing andThere is an effect that a fuel injection control device for a direct injection engine in which the accuracy of the fuel injection amount is improved by optimization is obtained.
[0158]
In addition, the present inventionClaim 2According toClaim 1The dead time correction means corrects the invalid pulse width based on the detected fuel pressure only when the fuel pressure deviation continuously exceeds a predetermined value for a predetermined time or more, and based on the target fuel pressure when the condition is not satisfied. Since the invalid pulse width is corrected by the correction, the correction of the injection pulse width is stabilized and optimized, so that there is an effect that a fuel injection control device for a direct injection engine with improved accuracy of the fuel injection amount can be obtained.
[0159]
In addition, the present inventionClaim 3According toClaim 1In the above, the injection pulse calculating means corrects the effective pulse width based on the target fuel pressure when the fuel pressure deviation is within a predetermined value, and when the fuel pressure deviation exceeds the predetermined value, the effective pulse based on the detected fuel pressure. Since the width is corrected, the correction of the injection pulse width is further optimized, and there is an effect that a fuel injection control device for a direct injection engine in which the accuracy of the fuel injection amount is improved.
[0160]
In addition, the present inventionClaim 4According toClaims 1 to 3One ofIn one sectionSince the predetermined value is changed in accordance with the target fuel pressure, the correction of the injection pulse width is optimized irrespective of the operating state, and the fuel of the direct injection engine in which the accuracy of the fuel injection amount is improved. There is an effect that an injection control device can be obtained.
[0161]
In addition, the present inventionClaim 5According toClaims 1 to 4One ofIn one sectionSince the predetermined value is set to a value equal to or higher than the pulsation component that is constantly superimposed on the detected fuel pressure, the correction of the injection pulse width is optimized regardless of the operation state, and the accuracy of the fuel injection amount is improved. This has the effect of obtaining a fuel injection control device for a direct injection engine.
[0162]
In addition, the present inventionClaim 6According toClaims 1 to 5One ofIn one sectionIn the meantime, a failure determination means for determining a failure of the fuel pressure detection means is provided, and the dead time correction means corrects the injection pulse width based on the target fuel pressure when the failure of the fuel pressure detection means is determined. Even if the fuel pressure detecting means fails, the correction of the injection pulse width is optimized, and the fuel injection control device of the direct injection engine with improved accuracy of the fuel injection amount can be obtained.
[0163]
In addition, the present inventionClaim 7According toVarious sensors for detecting the operating state of the engine, an injector for directly injecting fuel into the cylinder of the engine, a fuel pressure detecting means for detecting the fuel pressure acting on the injector, and an injection pulse of the injector based on the fuel pressure detected by the fuel pressure detecting means. In a fuel injection control device for a direct injection engine having an injection pulse calculating means for calculating a width, a dead time correcting means for correcting an invalid pulse width of an injector according to a detected fuel pressure;Mean fuel pressure calculating means for calculating mean fuel pressure from detected fuel pressureIs provided, the injection pulse calculating means calculates the injection pulse width by adding the effective pulse width and the invalid pulse width according to the operation state,The dead time correction means corrects the invalid pulse width based on the average fuel pressure when the fuel pressure deviation between the detected fuel pressure and the average fuel pressure is within a predetermined value, and detects the detected fuel pressure when the fuel pressure deviation exceeds the predetermined value. The invalid pulse width is corrected on the basis of the following formula, so that the correction of the injection pulse width is optimized irrespective of the operating state, and the fuel injection control device of the direct injection engine with improved accuracy of the fuel injection amount can be obtained. effective.
[0164]
In addition, the present inventionClaim 8According toClaim 7The dead time correction means corrects the invalid pulse width based on the detected fuel pressure only when the fuel pressure deviation continuously exceeds a predetermined value for a predetermined time or more, and based on the average fuel pressure when the condition is not satisfied. To correct the invalid pulse width, thereby optimizing the correction of the injection pulse width irrespective of the operation state, and obtaining the fuel injection control device of the direct injection engine with improved accuracy of the fuel injection amount. is there.
[0165]
In addition, the present inventionClaim 9According toClaim 7In the above, the injection pulse calculating means corrects the effective pulse width based on the average fuel pressure when the fuel pressure deviation is within a predetermined value, and when the fuel pressure deviation exceeds the predetermined value, the effective pulse width based on the detected fuel pressure. Since the width is corrected, the correction of the injection pulse width is further optimized, and there is an effect that a fuel injection control device for a direct injection engine in which the accuracy of the fuel injection amount is improved.
[0166]
In addition, the present inventionClaim 10According toClaims 7 to 9One ofIn one sectionSince the predetermined value is changed in accordance with the average fuel pressure, the correction of the injection pulse width is optimized irrespective of the operating state, and the fuel of the direct injection engine in which the accuracy of the fuel injection amount is improved. There is an effect that an injection control device can be obtained.
[0167]
In addition, the present inventionClaim 11According toClaims 1 to 10One ofIn one sectionSince the predetermined value is changed according to the engine speed, the correction of the injection pulse width is optimized irrespective of the operation state, and the accuracy of the fuel injection amount is improved in the cylinder injection engine. There is an effect that a fuel injection control device can be obtained.
[0168]
According to claim 12 of the present invention,Claims 1 to 11One ofIn one sectionSince the predetermined value is changed according to the injection amount of the injector, the correction of the injection pulse width is optimized irrespective of the operating state, and the in-cylinder injection engine with improved accuracy of the fuel injection amount is provided. This has the effect of obtaining the fuel injection control device described above.
[Brief description of the drawings]
FIG. 1 is a first embodiment of the present invention;Equipment related toFIG. 3 is a functional block diagram showing a main part of FIG.
FIG. 2The device of FIG.FIG. 4 is a characteristic diagram showing flow characteristics according to the present invention.
FIG. 3The device of FIG.5 is a flowchart showing a method of correcting an invalid pulse width according to the first embodiment.
FIG. 4 of the present invention.Embodiment 16 is a timing chart showing changes in fuel pressure behavior and target fuel pressure according to the present invention.
FIG. 5 of the present invention.Embodiment 19 is a flowchart showing a process of correcting an invalid pulse width according to the first embodiment.
FIG. 6 of the present invention.Embodiment 29 is a flowchart showing a process of correcting an invalid pulse width according to the first embodiment.
FIG. 7 of the present invention.Embodiment 36 is a timing chart showing changes in the fuel pressure behavior and the average fuel pressure according to the present invention.
FIG. 8 of the present invention.Embodiment 4FIG. 7 is an explanatory diagram showing a predetermined value changed and set with respect to a target fuel pressure according to FIG.
FIG. 9 of the present invention.Embodiment 4FIG. 7 is an explanatory diagram showing a predetermined value changed and set for an engine speed by the following.
FIG. 10 of the present invention.Embodiment 4FIG. 5 is an explanatory diagram showing a predetermined value changed and set for a fuel injection amount according to FIG.
FIG. 11 of the present invention.Embodiment 49 is a flowchart showing a process for changing a predetermined value according to the embodiment.
FIG. 12 of the present invention.Embodiment 59 is a flowchart showing a process of switching fuel pressure information according to the first embodiment.
FIG. 13 is a block diagram schematically showing a fuel supply system of a general fuel injection control device for a direct injection engine.
FIG. 14 is a functional block diagram showing a main part of a conventional fuel injection control device for a direct injection engine.
FIG. 15 is a characteristic diagram showing a flow rate characteristic by a conventional fuel injection control device for a direct injection engine.
[Explanation of symbols]
Reference Signs List 1 engine, 1F injector, 2 various sensors, 7 high-pressure pump, 10 high-pressure regulator (fuel pressure regulator), 12 fuel pressure sensor, 20A ECU, 21 intake amount detecting means, 22 rotation speed detecting means, 23 fuel pressure detecting means, 24 injection amount calculation Means, 25 injection amount correction means, 27 adder, 28 fuel pressure control means, 29 dead time correction means, 52 correction table, 91 dead time correction table, CNT time measurement counter, D predetermined value, J injection pulse signal, Kh correction coefficient , Kp fuel pressure ratio, Ne engine speed, PF detected fuel pressure, PFm average fuel pressure, PFO target fuel pressure, Qa intake air amount, Qf fuel injection amount, Ri exciting current, TJ injection pulse width, TD invalid pulse width, Te effective pulse width, Effective pulse width after Th correction, ΔPF fuel pressure deviation, ΔPFm average fuel , DerutaPFe pulsation width (ripple component), S110, S205, S207 retrieving invalid pulse width,
S111 Step of calculating the injection pulse width, S203 Step of comparing the fuel pressure deviation with a predetermined value, S302 Step of determining a predetermined time, S303 Time measurement step, S404 Step of changing a predetermined value, S501 Determining failure of the fuel pressure detecting means Step.

Claims (12)

Various sensors for detecting the operating state of the engine,
An injector for directly injecting fuel into a cylinder of the engine;
Fuel pressure detecting means for detecting a fuel pressure acting on the injector;
An injection pulse calculating means for calculating an injection pulse width of the injector based on a fuel pressure detected by the fuel pressure detecting means.
Dead time correction means for correcting the invalid pulse width of the injector according to the detected fuel pressure ;
Fuel pressure control means for controlling the fuel pressure acting on the injector to a target fuel pressure according to the operating state,
The injection pulse calculating means calculates the injection pulse width by adding the effective pulse width and the invalid pulse width according to the operation state ,
The dead time correction means,
If the fuel pressure deviation between the detected fuel pressure and the target fuel pressure is within a predetermined value, the invalid pulse width is corrected based on the target fuel pressure,
The fuel injection control device for a direct injection engine, wherein the invalid pulse width is corrected based on the detected fuel pressure when the fuel pressure deviation exceeds the predetermined value . The dead time correction means,
Only when the fuel pressure deviation exceeds the predetermined value continuously for a predetermined time or more, the invalid pulse width is corrected based on the detected fuel pressure,
The fuel injection control device for a direct injection engine according to claim 1 , wherein the invalid pulse width is corrected based on the target fuel pressure when the condition is not satisfied. The injection pulse calculation means,
When the fuel pressure deviation is within the predetermined value, the effective pulse width is corrected based on the target fuel pressure,
2. The fuel injection control device for a direct injection engine according to claim 1 , wherein when the fuel pressure deviation exceeds the predetermined value, the effective pulse width is corrected based on the detected fuel pressure. Wherein the predetermined value, the fuel injection control apparatus for a direct injection engine according to any one of claims 1 to 3, characterized in that is changed according to the target fuel pressure. Wherein the predetermined value, the cylinder injection engine according to any one of claims 1 to 4, wherein the set to a value of more than pulsation components regularly is superimposed on the detection fuel pressure Fuel injection control device. Comprising a failure determination means for determining a failure of the fuel pressure detection means,
The dead time compensation means, when a failure of said fuel pressure detecting means is determined, any one of claims 1, characterized in that to correct the injection pulse width based on the target fuel pressure to claim 5 13. A fuel injection control device for a direct injection engine according to item 13. Various sensors for detecting the operating state of the engine,
An injector for directly injecting fuel into a cylinder of the engine;
Fuel pressure detecting means for detecting a fuel pressure acting on the injector;
An injection pulse calculating means for calculating an injection pulse width of the injector based on a fuel pressure detected by the fuel pressure detecting means;
In a fuel injection control device for a direct injection engine having:
Dead time correction means for correcting the invalid pulse width of the injector according to the detected fuel pressure;
Average fuel pressure calculating means for calculating an average fuel pressure from the detected fuel pressure ,
The injection pulse calculating means calculates the injection pulse width by adding the effective pulse width and the invalid pulse width according to the operation state,
The dead time correction means,
When the fuel pressure deviation between the detected fuel pressure and the average fuel pressure is within a predetermined value, the invalid pulse width is corrected based on the average fuel pressure,
The fuel injection control device for a direct injection engine, wherein the invalid pulse width is corrected based on the detected fuel pressure when the fuel pressure deviation exceeds the predetermined value. The dead time correction means,
Only when the fuel pressure deviation exceeds the predetermined value continuously for a predetermined time or more, the invalid pulse width is corrected based on the detected fuel pressure,
The fuel injection control device for a direct injection engine according to claim 7 , wherein when the condition is not satisfied, the invalid pulse width is corrected based on the average fuel pressure. The injection pulse calculation means,
If the fuel pressure deviation is within the predetermined value, correct the effective pulse width based on the average fuel pressure,
The fuel injection control device for a direct injection engine according to claim 7 , wherein when the fuel pressure deviation exceeds the predetermined value, the effective pulse width is corrected based on the detected fuel pressure. The fuel injection control device for a direct injection engine according to any one of claims 7 to 9 , wherein the predetermined value is changed according to the average fuel pressure. Wherein the predetermined value, the fuel injection control apparatus for a direct injection engine according to any one of claims 1, characterized in that is changed according to the engine rotational speed to claim 10. Wherein the predetermined value, the fuel injection control apparatus for a direct injection engine according to any one of claims 1 to 11, characterized in that it is changed in accordance with the injection amount of the injector.

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