JPH09317545A - Fuel injection timing controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a good response to transition and good stability in normal state by setting a constant used for the advance control of a base value for controlling an injection timing control valve from the output of operation state detecting means and by conducting an advance correction by this constant and by calculating a final control value of the injection timing control valve and by driving the valve based on the calculated results. SOLUTION: An engine speed Ne and a fuel injection amount Qsol are read (s31) and actual fuel injection timing is calculated and a base value D-tcvo of a timing valve (TCV) duty is calculated. The base vale D-tcvo of a timing valve (TCV) duty is compared with the previous value D-tcvo (s32) and, when the former is larger than the latter, an equivalent Ttcva of a TCV time constant when TCV duty is increased is selected from a table and is substituted into Ttcva (s34) and a prescribed value GKITA is substituted into an advance correction gain Gkit when the TCV duty is increased (s35) and, when the former is smaller than the latter, a TTCVR of a TCV operation time constant when TCV duty is decreased is substituted into Ttcv (s36) and a prescribed value GKITR is substituted into an advance correction gain Gkit when the TCV duty is decreased (s37). The duty value D-tcv to be output is calculated by an equation using the base vale D-tcvo of the TCV duty value, the advance correction gain and an equivalent correction time constant Gkit and Ttcv.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection timing control system for an internal combustion engine, especially for a diesel engine.

[0002]

2. Description of the Related Art As a conventional fuel injection timing control method,
For example, there is a technique as disclosed in Japanese Patent Laid-Open No. 59-120735. This flow is shown in FIG. 16, which is for suddenly changing the duty value given to the timing control valve (injection timing control valve) during acceleration determination. First, it is determined whether or not it is a rapid acceleration, and if it is a rapid acceleration, it is determined whether or not it is the first determination. If it is the first, the timing control valve du
The ty value is calculated, the duty value is replaced with that value, and the processing ends. On the other hand, if the above determination is negative, the target advance amount is calculated from the accelerator opening and the engine speed, and on the other hand, the actual advance amount is calculated and the two are compared. If the target value is larger than the target value, the duty value is decreased, and if the target value is smaller, the duty value is increased and the processing ends.

On the other hand, in the advance correction, there is no technique for changing the correction method such as the correction gain depending on the fuel temperature.

[0004]

However, in the conventional fuel injection timing control method as described above, the duty value of the timing control valve is constant and changes between the steady state and the transient state, and the optimum duty value is always obtained. I found the problem that it was difficult to do. Further, it has been found that this size is more difficult because it needs to be changed depending on the fuel temperature.

The present invention has been made by paying attention to such a conventional problem. The duty value output to the timing control valve (TCV) is advanced and corrected while observing the characteristics and state of the pump, and finally the duty value is corrected. The above problem is solved by outputting the value to the timing control valve.

[0006]

In order to solve the above-mentioned problems, the present invention provides an operating condition detecting means for detecting engine operating conditions such as engine speed, accelerator opening, fuel temperature, and the like. Target injection timing setting means for setting the target injection timing from the output, actual injection timing detection means for detecting the actual injection timing, and injection timing delay for calculating the delay amount of the actual injection timing based on all the above means. Quantity calculation means,
An injection timing correction means for correcting the actual injection timing based on the calculation result by the calculation means; a basic control amount calculation means for calculating a control basic value to be output based on the output of the correction signal by the correction means; Lead control constant setting means for setting a constant used for lead control of the injection timing control valve control basic value from the output of the operating state detection means, and final injection timing control by performing lead correction from the output of the lead control constant setting means. The valve control value is calculated, and the valve driving means is used to drive the valve based on the advance correction calculation result.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. First, the configuration will be described. Operating state detecting means 1 for detecting engine operating states such as engine speed, accelerator opening, fuel temperature, and target injection timing setting for setting a target injection timing from the output of the operating state detecting means 1. Means 2, actual injection timing detection means 3 for detecting the actual injection timing, detection delay amount calculation means 4 for calculating the actual detection timing detection delay amount from the output of the operating state detection means 1, and actual injection timing detection The actual injection timing calculating means 5 for calculating the actual injection timing from the outputs of the means 3 and the detection delay amount calculating means 4, the target injection timing setting means 2 and the output of the actual injection timing calculating means 5 are output to the timing control valve duty. TCVduty calculation means 6 for calculating the basic value of the value, advance gain time constant setting means 7 for setting a constant used for advance correction from the output of the operating state detection means 1, and TCV a TCV control means 8 for advancing to the output value of the duty calculation means 6 and performing advance correction using the output value of the gain time constant setting means 7, and a TCV drive means 9 for driving a timing control valve from the output of the TCV control means 8. It is composed of.

Next, the operation will be described.

2 to 13 show the flow of this embodiment and the tables and maps required for it.

The advance correction calculation of the timing control valve duty according to the present invention will be described later with reference to FIGS. 9 to 14.

First, the calculation of TCVduty output to the timing control valve will be described with reference to FIG.

In step S1 (hereinafter, simply referred to as S1), a target injection timing Itsol is calculated.
The actual injection timing Itist is calculated in S2. In S3, the basic value D_tcv0 of the TCVduty value is obtained from the difference between Itsol and Itist using Kp, Ki, and Kd as in the normal PID control. In S4, constants Gkit and Ttcv used for advance correction are calculated. In S5, the process proceeds to D_tcv0 to perform correction (D_tcv), and the process ends. The method of advance correction and S1 and S2 will be described later.

FIG. 3 is a calculation flow of the target injection timing.

First, in S11, the engine speed Ne, the fuel injection amount Qsol representing the load, the start switch, the water temperature Tw, etc. are read. In S12, it is determined whether or not the start switch is currently on, and if so, the process proceeds to S13, and if not, the process proceeds to S15. In step 13, the starting injection timing correction value is retrieved from Tw from a table as shown in FIG.
Let t_tws. In S14, the injection timing correction value It_tw after starting is set to zero. In S15, the injection timing correction value after startup is searched from Tw, for example, in a table as shown in FIG. 5 to set It_tw, and in S16, the injection timing correction value I at startup is calculated.
Let t_tws be zero. In S17, the target injection timing It_ld is retrieved from Ne and Qsol from a map as shown in FIG. 6, for example. It_ld, It_tws, It_ in S18
tw is added and the target injection timing Itsol is set, and the processing ends.

FIG. 7 is a flow chart for calculating the actual injection timing.

First, in S21, operating states such as the engine speed Ne and the fuel injection amount Qsol are read. In S22, for example, the injection timing detection delay amount Itis is calculated from the map shown in FIG.
Search t_d. This is to experimentally set a hardware-based detection delay when detecting the actual injection timing. In S23, the injection timing Itist_dly from the sensor for detecting the actual injection timing is read, and in S24, Iist_dly is read.
The actual injection timing Itist is obtained by adding the list_dly and Itist_d, and the process ends.

FIG. 9 is a flow chart of the first embodiment for setting the advance correction constant. First, in S31, the engine speed Ne, the fuel injection amount Qsol, etc. are read. S32 for T
CVduty basic value D_tcv0 and D_t in the previous calculation
cv0 is compared. If the former is larger, the process proceeds to S33, and if the latter is larger, the process proceeds to S36. In S33, the TCVduty is calculated from the engine speed based on the table shown in FIG. 10, for example.
The value corresponding to the TCV operation time constant at the time of increase (value corresponding to the reciprocal of the time constant) Ttcva is searched for and substituted in Ttcv in S34. In S35, the predetermined value GKITA is substituted for the advance correction gain Gkit when TCVduty increases, and the process ends. In S36, the TCV operation time constant equivalent value (reciprocal equivalent value of the time constant) TTCVR when TCVduty is decreased is set to Ttcv.
To. In S37, the predetermined value GKITR is substituted for the advance correction gain Gkit when TCVduty is reduced, and the process is ended. This process is a setting method in which the time constant is large when TCV increases and is very small when TCV decreases. Therefore, FIG.
The characteristic of 0 is also set as such.

FIG. 11 is a flow chart of the second embodiment for setting the advance correction constant.

First, in S41, the engine speed Ne, the fuel injection amount Qsol, etc. are read. TCVduty in S42
The basic value D_tcv0 is compared with D_tcv0 at the time of the previous calculation, and if the former is larger, go to S43, and if the latter is larger, S4.
Go to 6. In step S43, the engine speed is calculated as shown in FIG.
TC when the TCVduty increases from the table shown in
V operation time constant equivalent value (reciprocal time constant equivalent value) Ttcva
Is searched and substituted in Ttcv in S44. T in S45
A predetermined value GKITA is substituted for the advance correction gain Gkit when the CVduty increases. At S46, the TCV operation time constant equivalent value when TCVduty decreases (equivalent to the reciprocal of the time constant) T
Substitute TCVR into Ttcv. In S47, TCVdu
A predetermined value GKIT for the advance correction gain Gkit when ty decreases
Substitute R. This process is a setting method in which the time constant is large when TCV increases and is very small when TCV decreases. Therefore, the characteristics shown in FIG. 10 are also set as such.

In S48, it is determined whether or not it is currently in the idle state. If it is in the idle state, the process proceeds to S51. If it is not in the idle state, the process proceeds to S49, the difference between the engine speed Ne and the engine speed Ne before the predetermined number of times is calculated, and if it is larger than the predetermined value DNETR, the process is ended as it is. S5 if small
The process proceeds to 0 and the difference between the fuel injection amount Qsol and the fuel injection amount Qsol before the predetermined number of times is calculated. If it is smaller, proceed to S51,
The difference between the accelerator opening degree Dcl and the accelerator opening degree Dcl before the predetermined number of times is calculated, and if it is larger than the predetermined value DDCTR, the process is ended, and if it is smaller, the routine proceeds to S52, where the advance correction gain Gk
The process is ended by setting it to 1 (no advance correction). In this process, from S48 to S52, constant setting is performed so that advance correction is not performed during idling or during steady operation.

FIG. 12 is a flow chart of the third embodiment for setting the advance correction constant.

First, in S61, the engine speed Ne, the fuel injection amount Qsol, etc. are read. In S62, the correction coefficient Ktcvtf is calculated from the fuel temperature Tf from the advance correction time constant equivalent value fuel temperature correction coefficient table as shown in FIG. 13, for example. S
At 63, the correction coefficient Kgkittf is calculated from the fuel temperature from the advance correction gain fuel temperature correction coefficient table as shown in FIG. 14, for example. TCVduty basic value D_tcv0 in S64
And D_tcv0 at the time of the previous calculation are compared. If the former is larger, the process proceeds to S65, and if the latter is larger, the process proceeds to S68. In step S65, the TCV operation time constant equivalent value (equivalent to the reciprocal of the time constant) Ttcva when the TCVduty increases is retrieved from the engine speed, for example, from a table as shown in FIG. . S
In 67, the advance correction gain Gki when TCVduty increases
t is multiplied by the predetermined value GKITA and the correction coefficient Kgkitttf and substituted, and the processing is ended. In S68, TCVduty
TCV operation time constant equivalent value at the time of decrease (value equivalent to the reciprocal of the time constant) TTCVR is multiplied by a correction coefficient Ktcvtf to obtain Ttc.
Substitute in v. At S69, the advance correction gain Gkit when TCVduty is reduced is set to a predetermined value GKITR and the correction coefficient Kg.
Multiply and substitute by kittf, and the process ends. This process is a setting method in which the time constant is large when TCV increases and is very small when TCV decreases. Therefore, the characteristics shown in FIG. 10 are also set as such. Further, in FIGS. 13 and 14, since the TCV operation time constant is large when the fuel temperature is low, the advance correction gain and the time constant equivalent value are set to be large.

FIG. 15 is a flow chart showing a method of advance correction calculation of the timing control valve.

First, in S71, the basic value D_tcv0 of the timing control valve duty value, the advance correction gain Gkit, and the advance correction time constant equivalent value Ttcv are read.
The duty value D that is finally output to the timing control valve after the advance correction processing is performed by the equation shown in S72.
Calculate _tcv. In step S73, the intermediate variable Rtcv is calculated by the equation shown in the figure, and the process ends.

[0026]

As described above, according to the present invention, transient followability and steady-state stability are corrected by correcting the timing control valve duty value that controls the injection timing according to the characteristics of the pump. Is secured,
It is possible to always achieve an appropriate injection timing. Steady-state stability has a great effect on emission reduction during steady-state operation, and transient follow-up performance also has a great effect on emission reduction during transition. Further, by changing the gain and time constant of the correction (advance correction method) depending on the fuel temperature, it becomes possible to perform optimum injection timing control during cold engine warm-up and warm-up engine warm-up. Also, in general, TCV
However, by performing the correction of the present invention, special processing at the time of starting is not required, and simplification of the logic can be achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a timing control valve duty calculation flow in the present invention.

FIG. 3 is a diagram showing a target injection timing calculation flow in the present invention.

FIG. 4 is a diagram showing an example of a startup injection timing correction amount table in the present invention.

FIG. 5 is a diagram showing an example of an injection timing water temperature correction table in the present invention.

FIG. 6 is a diagram showing an example of a target injection timing map in the present invention.

FIG. 7 is a diagram showing an actual injection timing calculation flow in the present invention.

FIG. 8 is a diagram showing an example of an injection timing detection delay map in the present invention.

FIG. 9 is a diagram showing a flow of advance correction constant calculation in the present invention.

FIG. 10 is a diagram showing an example of a TCV advance correction time constant equivalent value table in the present invention.

FIG. 11 is a diagram showing a flow of advance correction constant calculation in the present invention.

FIG. 12 is a diagram showing an advance correction constant calculation flow in the present invention.

FIG. 13 is a diagram showing an example of a fuel temperature correction coefficient table corresponding to a lead correction time constant in the present invention.

FIG. 14 is a diagram showing an example of a lead correction gain fuel temperature correction coefficient table in the present invention.

FIG. 15 is a diagram showing a TCV advance correction processing flow in the present invention.

FIG. 16 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Operating state detection means 2 Target injection timing setting means 3 Actual injection timing detection means 4 Detection delay amount calculation means 5 Actual injection timing calculation means 6 TCVduty calculation means 7 Advance gain time constant setting means 8 TCV control means 9 TCV drive means

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Claims (5)

[Claims] 1. An operating state detecting means for detecting an engine operating state such as an engine speed, an accelerator opening degree, a fuel temperature, and a target injection timing setting means for setting a target injection timing from an output of the operating state detecting means. An actual injection timing detection means for detecting the actual injection timing, an injection timing delay amount calculation means for calculating the actual injection timing delay amount based on all the above means, and an actual injection timing delay amount calculation means for calculating the actual injection timing delay amount based on the calculation results by the calculation means. An injection timing correction means for correcting the injection timing, a basic control amount calculation means for calculating a control basic value output based on the output of a correction signal by the correction means, and an injection timing control valve based on the output of the operating state detection means. Lead control constant setting means for setting a constant used for lead control of the control basic value, and a final injection timing control valve for performing lead correction from the output of the lead control constant setting means. Means for calculating a control value, 該進 viewed correction operation and valve driving means for driving the valve based on the result, the fuel injection timing control apparatus for an internal combustion engine, characterized in that it consists. 2. The advance control constant setting means sets a constant such that advance correction is prohibited or advance correction gain is reduced at idle.
13. A fuel injection timing control device for an internal combustion engine according to claim 10. 3. The fuel for an internal combustion engine according to claim 1, wherein the advance control constant setting means sets a constant that inhibits advance correction or reduces the advance correction gain during steady operation. Injection timing control device. 4. The fuel injection timing control device for an internal combustion engine according to claim 1, wherein the advance control constant setting means corrects the advance correction constant based on the fuel temperature. 5. The fuel injection for an internal combustion engine according to claim 4, wherein the advance control constant setting means sets the advance correction gain and / or the time constant to be larger as the fuel temperature is lower. Timing control device.