JPH0874644A - Injection timing control device of fuel injection pump - Google Patents

Abstract

PURPOSE: To enable achieving optimum combustion by performing injection timing feedback control appropriately to suit injection rate characteristics. CONSTITUTION: A fuel injection pump 1 which force-feeds fuel to a fuel injection nozzle 34 has its fuel injection timing regulated by a timer 25. The fuel injection nozzle 34 is provided with a needle valve lift sensor 35. An ECU 40 performs injection timing feedback control based on the deviation of actual injection timing, obtained from the result of detection by the needle valve lift sensor 25, from desired injection timing computed to match engine operating conditions; if the actual injection timing is advanced or retarded from the desired injection timing, the ECU 40 compensates a greater amount than the difference between them. The center position of the injection rate of the actual injection timing therefore coincides with that of the injection rate of the desired injection timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection timing control device for a fuel injection pump, which is provided with a fuel injection pump for pressure-feeding fuel to a fuel injection nozzle as an internal combustion engine operates. .

[0002]

2. Description of the Related Art In this type of injection timing control device, fuel is injected from a fuel injection nozzle at a desired timing.
The fuel injection timing is controlled by a timer of a fuel injection pump, and various techniques have been conventionally proposed for improving exhaust gas (emission) of an internal combustion engine and optimizing output. For example, there is an injection timing control device that detects an actual timer position and performs feedback control so as to eliminate a deviation between the timer position and a target timer position obtained from an engine operating state. However, a control device that performs such timer position feedback cannot correct the deviation between the target injection timing and the actual injection timing (actual injection timing) due to changes over time.
Specifically, when the valve opening pressure changes due to the deterioration of the fuel injection nozzle, or when the residual pressure in the injection pipe changes due to the low temperature of the fuel or the high viscosity of the fuel, the fuel pumping may start earlier. The actual injection timing will shift to the advanced side due to the increase in pipe pressure. Also, when pressure leaks in the fuel injection pump,
The actual injection timing is delayed. In this case, optimum injection timing control cannot be realized.

Further, in the injection timing control device for performing the above-mentioned timer position feedback control, the deviation between the actual injection timing obtained from the needle valve lift amount of the fuel injection nozzle and the target injection timing obtained according to the engine operating state. In order to eliminate this, there are some that perform feedback control. That is, in this device, the actual injection timing is detected by the needle valve lift sensor provided in the fuel injection nozzle, and the actual injection timing is reflected in the injection timing control. In such injection timing control, the control accuracy can be made even more precise. For example,
In the injection timing control device of Japanese Patent Laid-Open No. 62-210242, a decrease in valve opening pressure of the fuel injection nozzle is detected and an injection timing correction corresponding to the amount of decrease in valve opening pressure is performed.

[0004]

However, even with the feedback control of the actual injection timing as described above, the optimum injection timing control cannot be realized. This is for the following reason. FIG. 8 shows the injection rate curve of the target injection timing (see FIG.
“A”), the injection rate curve when the actual injection timing is shifted to the advance side (“B” in FIG. 8) and the injection rate curve when the actual injection timing is shifted to the delay side (FIG. 8) "C") is shown, and the upper part is the injection rate curve before correction and the lower part is the injection rate curve after correction. According to this FIG. 8, the injection rate curve is shown in the upper part of FIG.
In the case of a change such as B "or" C ", the injection timing correction is insufficient, such as when the injection timing (injection start timing) is simply adjusted as shown in the lower stage, such that a large deviation remains at the injection end timing. As a result, there arises a problem that the desired combustion cannot be obtained.

The present invention has been made by paying attention to the above problems, and its purpose is to appropriately perform injection timing feedback control based on the characteristics of the injection rate,
An object of the present invention is to provide an injection timing control device for a fuel injection pump that can realize optimal combustion.

[0006]

In order to achieve the above object, in the present invention, the injection timing is corrected according to the relationship between the deviation of the injection timing to the advance side or the delay side and the injection rate characteristic at that time. . That is, as can be seen from FIG. 8 described above, when the injection timing shifts to the advance side (in the case of curve B),
As the injection period becomes shorter, the peak of the injection rate becomes higher,
The position of the center of gravity of the injection rate shifts to the leading side with respect to the difference between the actual injection timing and the target injection timing. This is because, as described above, the deviation of the actual injection timing to the advance side is caused by the early start of the fuel pumping and the rise in the pipe internal pressure. On the contrary, when the injection timing is shifted to the delay side (in the case of the curve C), the injection period becomes longer and the peak of the injection rate becomes lower. Also shifts to the delay side. This is because the shift of the actual injection timing to the delay side is due to the fuel leakage in the fuel injection pump. From this, in the present invention, the injection timing control device is configured as follows, focusing on the position of the center of gravity of the injection rate.

According to the first aspect of the invention, as shown in FIG. 9, the fuel is sucked and pressurized as the internal combustion engine M1 is operated, and the pressurized high pressure fuel is supplied to the fuel injection nozzle M2. Fuel injection pump M3 and the fuel injection nozzle M2
And an actual injection timing detection means M4 for detecting the actual fuel injection timing by the fuel injection pump M3,
A timer M5 for adjusting the injection timing by the fuel injection pump M3, a target injection timing calculating means M6 for calculating a target injection timing according to the engine operating state, and an actual injection detected by the actual injection timing detecting means M4. The position of the center of gravity of the injection rate at the time coincides with the position of the center of gravity of the injection rate of the target injection timing calculated by the target injection timing calculation means M6.
An injection timing correction means M7 for correcting the target injection timing,
Injection timing control means M8 for controlling the timer M5 based on the injection timing corrected by the injection timing correction means M7.
The point is to have and.

According to the second aspect of the present invention, the injection timing correcting means M7 corrects the amount larger than the difference between the actual injection timing and the target injection timing if the actual injection timing is ahead or behind the target injection timing.

In the third aspect of the present invention, the injection timing correction means M7 increases the correction amount in the excessive direction as the operating load of the internal combustion engine M1 increases or the engine speed decreases.

According to a fourth aspect of the present invention, a fuel injection pump M3 is set with a pump reference angle with respect to a reference crank angle of the internal combustion engine M1. In, the deviation between the actual reference angle detection means for detecting the actual pump reference angle of the fuel injection pump M3, the actual pump reference angle by the actual reference angle detection means, and the preset target pump reference angle is calculated. And a reference angle deviation amount calculating means for calculating,
The target injection timing calculation means M6 calculates a target injection timing with respect to the pump reference angle, and the injection timing correction means M7 calculates the target injection timing according to the deviation amount of the pump reference angle calculated by the reference angle deviation amount calculation means. To correct.

[0011]

According to the first aspect of the invention, the fuel injection pump M3 sucks and pressurizes the fuel as the internal combustion engine M1 operates, and the pressurized high-pressure fuel is injected into the fuel injection nozzle M2.
Supply to. The actual injection timing detection means M4 detects the actual fuel injection timing of the fuel injection nozzle M2. The target injection timing calculation means M6 calculates the target injection timing according to the engine operating state. The injection timing correction means M7 matches the center of gravity position of the injection rate of the actual injection timing detected by the actual injection timing detection means M4 with the center of gravity position of the injection rate of the target injection timing calculated by the target injection timing calculation means M6. So that the target injection timing is corrected. The injection timing control means M8 controls the timer M5 based on the injection timing corrected by the injection timing correction means M7.

In short, deterioration of the fuel injection nozzle M2, etc.
When there is a deviation between the target injection timing and the actual injection timing due to the change over time, the characteristics of the injection rate change and the center of gravity position of the injection rate shifts to the advance side or the delay side. However, according to this configuration, the injection timing is corrected so that the center of gravity of the injection rate at the target injection timing and the center of gravity of the injection rate at the actual injection timing match, so that even if the injection rate characteristic changes, Combustion is realized.

According to the second aspect of the invention, the injection timing correction means M7 corrects the amount larger than the difference between the actual injection timing and the target injection timing if the actual injection timing is ahead or behind the target injection timing. That is, as described above, the position of the center of gravity of the injection rate shifts further to the leading side than the difference between the actual injection timing and the target injection timing when the injection timing deviates to the leading side, and conversely, the injection timing falls to the lagging side. When it deviates to, it deviates further to the delay side from the difference between the actual injection timing and the target injection timing. Therefore, by correcting the deviation between the above two injection timings excessively, more accurate injection timing correction becomes possible.

According to the third aspect of the invention, the injection timing correction means M7 increases the correction amount in the excessive direction as the operating load of the internal combustion engine M1 increases or the engine speed decreases. That is, when the operating load of the internal combustion engine M1 is large or the engine speed is small, the change in the injection rate (deviation of the position of the center of gravity) due to the increase of the fuel pressure or the fuel leakage becomes large. Appropriate injection timing control is realized.

According to the fourth aspect of the present invention, the actual reference angle detecting means detects the actual pump reference angle of the fuel injection pump M3 with respect to the reference crank angle of the internal combustion engine M1. The reference angle deviation amount detecting means calculates the deviation between the actual pump reference angle detected by the actual reference angle detecting means and the preset target pump reference angle. The target injection timing calculation means M6 calculates the target injection timing with respect to the pump reference angle, and the injection timing correction means M7 corrects the target injection timing according to the deviation amount of the pump reference angle calculated by the reference angle deviation amount calculation means. That is, when the injection timing by the fuel injection pump M3 is controlled at the target injection timing with respect to the reference crank angle of the internal combustion engine M1, the injection timing may be shifted due to individual differences such as an assembly error of the fuel injection pump M3. . However, according to this structure, those inconveniences are eliminated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a fuel injection control device for a fuel injection pump for a diesel engine will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a fuel injection control device in this embodiment. In the electromagnetic spill type distribution type fuel injection pump 1 shown in FIG.
The drive shaft 3 is rotatably supported by
One end of this drive shaft 3 is the pump housing 2
Exposed to the outside. A vane type feed pump 4 is provided inside the pump housing 2 (shown in 90 degrees in FIG. 1).
The feed pump 4 sucks up fuel by the rotation of the drive shaft 3 and sends it to the fuel chamber 5.
A pulsar 6 having a plurality of teeth on the outer peripheral surface is attached to the drive shaft 3, and a cam plate 7 is connected to the tip end portion of the drive shaft 3 via a coupling (not shown).

A roller ring 8 is arranged between the pulsar 6 and the cam plate 7, and a plurality of cam rollers 9 facing the face cam 7a of the cam plate 7 are attached to the roller ring 8. The face cams 7a are provided in the same number as the number of cylinders of the diesel engine. The cam plate 7 is constantly driven by the spring 12 to the cam roller 9
Urging contact with. A plunger 11 is arranged in a cylinder 10 arranged on the right side of the pump housing 2, and the plunger 11 is supported by a cam plate 7 so as to be integrally rotatable. Therefore, the cam plate 7 and the plunger 11 rotate with the rotation of the drive shaft 3 and reciprocate in the left-right direction in the figure by the cam roller 9. At this time, the fuel is sucked into the pressurizing chamber 14 through the suction passage 13 and is pressurized by the rotation and reciprocating motion of the plunger 11. The pressurized fuel is distributed to the distribution passage 15,
It is supplied to the fuel injection nozzle 34 of the engine 33 through the delivery valve 16.

A fuel cut valve (FC) is provided in the middle of the suction passage 13 (communication passage between the fuel chamber 5 and the pressurizing chamber 14).
V) 17 is arranged. This fuel cut valve 17
By energizing (turning on) the coil 18, the valve body 19 is moved to the open position, and the suction of fuel from the fuel chamber 5 to the pressurizing chamber 14 is permitted. When the coil 18 is not energized (OFF), the valve body 19 is moved to the closed position to stop the fuel suction.

Further, the pump housing 2 is formed with a spill passage 20 which communicates the fuel chamber 5 with the pressurizing chamber 14, and an electromagnetic spill valve 21 is provided in the spill passage 20.
Is arranged. This electromagnetic spill valve 21 has a coil 2
When the valve 2 is not energized (OFF), the valve body 23 is moved to the open position to spill the fuel in the pressurizing chamber 14 into the fuel chamber 5 through the spill passage 20. Also, the coil 22 is energized (ON)
At times, the valve body 23 is moved to the closed position to stop the spill of fuel from the pressurizing chamber 14 to the fuel chamber 5. By the opening / closing operation of the electromagnetic spill valve 21, a fuel injection nozzle 34 described later
The fuel injection amount is adjusted to a predetermined amount.

Further, a hydraulic timer 25 (shown in 90 degrees development in FIG. 1) for adjusting the fuel injection timing is built in the lower part of the pump. The timer 25 is the fuel chamber 5
The timer piston 27 disposed inside the timer housing 26 is connected to the roller ring 8 via a slide pin 28. The timer piston 27 is connected to the feed pump 4
Due to the balance between the change in the hydraulic pressure due to the change and the spring force of the timer spring 29, the roller ring 8 slides in the left-right direction in the figure, and the roller ring 8 rotates by this movement.

The fuel pressure of the timer 25 is adjusted by opening / closing the timer control valve (TCV) 30 by controlling the duty ratio. Then, the position of the timer piston 27 is adjusted as the fuel pressure is adjusted by the timer control valve 30. Then, the lift timing of the plunger 11 is adjusted according to the rotation of the roller ring 8, and the fuel injection timing is controlled. The longer the drive (ON) time of the timer control valve 30, that is, the larger the command duty ratio signal, the more the fuel injection timing is controlled toward the retard side, and the shorter the drive (ON) time, that is, the command duty ratio signal. Is smaller, the fuel injection timing is controlled to the advanced side.

The fuel chamber 5 in the pump housing 2 is provided with a rotation angle sensor 31 composed of an electromagnetic pickup coil. The rotation angle sensor 31 detects the passage of teeth provided on the outer peripheral portion of the pulsar 6 made of a magnetic material. In addition,
The pulsar 6 is formed with, for example, convex teeth at every 3.75 ° (corresponding to 7.5 ° CA), and several teeth are cut out at the same intervals as the number of engine cylinders. A toothless portion is provided. Therefore, when the pulser 6 rotates together with the drive shaft 3, the rotation angle sensor 31 outputs a pulse signal every time a tooth passes. Here, the pulsar 6 is a pump TDC in which the pressure chamber 14 is minimized by the plunger 11.
The relative position is set so that one of the toothless portions approaches the rotation angle sensor 31 at the position (pump reference angle) and the pump TDC signal is output.

On the other hand, the engine 33 is provided with a fuel injection nozzle 34 for injecting and supplying the fuel pumped from the fuel injection pump 1 to the engine 33. The fuel injection nozzle 34 is provided with a needle valve lift sensor 35 that measures a vortex loss associated with the needle valve lift.
5 outputs a voltage signal corresponding to the needle valve lift amount. Further, around the engine 33, an accelerator sensor 36 for detecting an accelerator opening, a water temperature sensor 37 for detecting a temperature of engine cooling water, and an engine TDC sensor 38 for outputting an engine TDC signal (reference crank angle signal) are provided. Has been.

Electronic control unit (hereinafter referred to as ECU) 40
Is mainly composed of a microcomputer (not shown) including a CPU, a memory, an input / output interface and the like. The ECU 40 includes a rotation angle sensor 31, an accelerator sensor 36, a water temperature sensor 37, and an engine TDC sensor 38.
Engine operation information is detected based on input signals from various sensors such as. Further, the ECU 40 detects the timing (actual injection timing) at which fuel injection actually starts based on the output signal of the needle valve lift sensor 35.

In the present embodiment, the needle valve lift sensor 3
5 and the ECU 40 constitute an actual injection timing detection means, and the ECU 40 constitutes a target injection timing calculation means, an injection timing correction means, and an injection timing control means. Also,
The rotation angle sensor 31 constitutes an actual reference angle detecting means, and the ECU 40 constitutes a reference angle deviation amount calculating means.

Next, the operation of the fuel injection control device constructed as described above will be described. FIG. 2 is a flow chart showing a fuel injection timing control routine in this embodiment, and the routine is executed by the ECU 40 at predetermined time intervals. FIG. 3 is a timing chart showing various signals related to fuel injection.

First, the outline of the fuel injection control will be described with reference to FIG. In FIG. 3, the actual pump TDC is displaced from the engine TDC by θ _T (hereinafter, referred to as TDC actual advance amount θ _T ) to the advance side. In design, θ
_The advance angle of _TO (hereinafter, referred to as TDC target advance angle amount θ _TO ) is given in advance. At this time, the actual pump TDC and the design target pump TDC deviate by Δθ _T (hereinafter, referred to as the first advance angle correction amount Δθ _T ).

Further, the target injection timing θ _PO and the actual injection timing θ
_P is set for the actual pump TDC, and the difference (θ _PO −θ _P ) between the two injection timings is the second advance angle correction amount Δθ _P. Then, the injection timing is corrected by the first advance angle correction amount Δθ _T and the second advance angle correction amount Δθ _P.

The fuel injection timing control routine will be described below with reference to the flowchart of FIG. Now, when this routine starts, the ECU 40 firstly executes steps 100-1.
At 06, the detection data of various sensors are input. For more information,
In step 100, engine speed data based on the detection result of the rotation angle sensor 31, in step 101 accelerator opening data based on the detection result of the accelerator sensor 36, and in step 102 cooling water temperature data based on the detection result of the water temperature sensor 37. , In step 103 engine T
The engine TDC data based on the detection result of the DC sensor 38, the actual pump TDC data based on the detection result of the rotation angle sensor 31 in step 104, and the pump phase angle data based on the detection result of the rotation angle sensor 31 in step 105, In step 106, the needle valve lift sensor 3
The needle valve lift data of the fuel injection nozzle 34 based on the detection result of No. 5 is input.

After that, the ECU 40 proceeds to step 107.
Pre-set TDC target advance angle θ_TOAnd the above
Input data of engine 103, 104 (engine TDC data
Data, actual pump TDC data)
Angular amount θ_TAnd read. Then, the ECU 40
At step 108, the TDC target advance angle θ_TOTo TDC real
Advance angle θ_TTo subtract the first advance correction amount Δθ_TCalculate
(Δθ_T= Θ_TO−θ _T). Here, the first advance angle correction amount
Δθ_TIs a pulsar when the fuel injection pump 1 is assembled.
6, it corresponds to the assembly error of the roller ring 8 etc.
If so, the TDC target advance angle θ_TOAnd TDC actual advance angle θ
_TAnd Δθ_T= 0.

Further, the ECU 40 outputs the power in step 109.
Target injection timing θ for the pump TDC _POAnd also the pump
Actual injection timing θ with respect to TDC_PAnd calculate. here,
Target injection timing θ_POIs the calculation map stored in memory.
Engine speed, accelerator opening and cooling at that time
It is required according to the water temperature. Also, the actual injection timing θ_PIs a needle
Obtained by differentiation of the needle valve lift signal by the valve lift sensor 35
Can be Subsequently, the ECU 40 goes up in step 110.
Target injection timing θ_POTo actual injection timing θ_PSecond by subtracting
Advance angle correction amount Δθ_PIs calculated (Δθ_P= Θ_PO−
θ_P).

Thereafter, in step 111, the ECU 40 adds a correction amount obtained by multiplying the second advance correction amount Δθ _P by a coefficient α (where 1 <α <2) to the first advance correction amount Δθ _T. To obtain the final advance angle correction amount Δθ (Δθ = Δθ _T + α ・ Δ
θ _P ). Here, the coefficient α is a coefficient for matching the barycentric position of the target injection rate with the barycentric position of the actual injection rate, and is calculated using the table of FIG. 4. In the table of FIG. 4, the coefficient α is set to increase as the load (accelerator opening) increases or the engine speed decreases. This is because when the engine load is large or the engine speed is low, the change in the injection rate (deviation of the center of gravity) due to the increase in fuel pressure or fuel leakage becomes large.

Finally, the ECU 40 outputs the final advance correction amount Δθ in step 112 to drive the timer control valve 30. Next, the effect obtained by the above processing will be described with reference to FIG. FIG. 5A shows a case where the actual injection timing is ahead of the target injection timing, and FIG. 5B shows a case where it is also behind. In addition, FIG.
In (b), the solid line shows the target injection rate curve, the broken line shows the actual injection rate curve, the upper row shows the injection rate curve before correction, and the lower row shows the injection rate curve after correction. According to FIGS. 5A and 5B, when the injection timing is corrected to the delay side or the advance side, a value (α · Δθ) larger than the difference (Δθ _P ) between the target injection timing and the actual injection timing is obtained. _P )
You can see that the correction is done in.

That is, in the case of FIG. 5A, the injection period is shorter in the actual injection rate curve (broken line) than in the target injection rate curve (solid line), and the peak of the actual injection rate curve is the target injection rate curve. It is higher than the peak of the rate curve. That is,
The position of the center of gravity of the injection rate is further displaced from the advance amount of the injection timing. This is because the reason why the actual injection timing is shifted to the advance side is that the fuel injection start is accelerated and the pipe internal pressure is increased mainly due to deterioration of the fuel injection nozzle 34 and the like.
Therefore, in this case, it is not enough to correct only the difference (Δθ _P ) between the target injection timing and the actual injection timing, and excessive correction is performed based on the actual injection rate curve.

On the other hand, in the case of FIG. 5B, the actual injection rate curve (broken line) has a longer injection period than the target injection rate curve (solid line), and the peak of the actual injection rate curve is the target injection rate curve. It is lower than the peak of the rate curve. That is, the position of the center of gravity of the injection rate is further shifted toward the delay side than the delay amount of the injection timing. This is because the actual injection timing is deviated to the delay side mainly due to fuel leakage around the plunger 11 in the fuel injection pump 1 and the like, and in this case too, the overcorrection is performed as in the above.

As described in detail above, according to the injection timing control device of this embodiment, when the actual injection timing is on the advance side or the delay side of the target injection timing, the correction amount larger than the difference between the two injection timings is used. To do. As a result, the position of the center of gravity of the injection rate at the actual injection timing and the position of the center of gravity of the injection rate at the target injection timing can be substantially matched, and the fuel injection nozzle 34
The injection timing feedback control can be appropriately performed even when the characteristics of the injection rate change such as when the fuel injection deteriorates.
And optimal combustion can be realized.

Further, in this embodiment, the larger the engine load or the smaller the engine speed, the larger the correction amount in the excessive direction. That is, when the engine load is large or the engine speed is small, the change in the injection rate due to the increase in the fuel pressure or the fuel leakage becomes large. However, by performing the above correction, more appropriate injection timing control can be realized. it can.

Further, in this embodiment, the deviation between the actual pump TDC and the target pump TDC is calculated, and the deviation amount is reflected in the injection timing correction. That is, when the injection timing by the fuel injection pump 1 is controlled at the target injection timing for the engine TDC, the injection timing may deviate due to an individual difference due to an assembly error of the fuel injection pump 1 or the like. If so, those inconveniences are eliminated.

(Second Embodiment) The injection timing control device according to the second embodiment will be described below, focusing on the differences from the first embodiment.

The flowchart of FIG. 6 shows a fuel injection timing control routine in the second embodiment. This routine is performed in steps 100 to 10 of the routine shown in FIG.
8 and step 112 are common parts, and steps 109 to 111 in FIG. 2 are replaced with steps 200 to 203 in FIG.
Is replaced with.

Now, referring to FIG. 6, in step 200 following step 108 in FIG. 2, the ECU 40 sets the center position of the target injection period (this is the target center angle θ _XO ).
To calculate. That is, the ECU 40 controls the engine operating state at that time (engine speed, accelerator opening, cooling water temperature).
A target injection period of fuel injection (target injection start timing and target injection end timing) is calculated according to the above, and a target center angle θ _XO which is an intermediate value between the target injection start timing and the target injection end timing is calculated. At this time, the target center angle θ _XO is
It almost coincides with the position of the center of gravity of the injection rate in the target injection period.

The ECU 40 determines in step 201 the actual fuel consumption.
Center position of material injection period (This is the actual center angle θ_XTosu
Calculate). That is, the ECU 40 determines that the needle valve lift
From the output signal of the sensor 35 to the actual injection period (at the start of actual injection
Period and the actual injection end timing)
Actual center angle θ, which is the intermediate value between the start timing and the actual injection end timing
_XTo calculate. At this time, the actual center angle θ_XIs the actual injection period
It almost coincides with the position of the center of gravity of the injection rate. In addition, in target
Heart angle θ_XOAnd actual center angle θ_XIs for the pump TDC
Angle.

Then, in step 202, the ECU 40 subtracts the actual center angle θ _X from the target center angle θ _XO to calculate a third advance correction amount Δθ _X (Δθ _X = θ _XO −
θ _X ). Further, the ECU 40 executes step 203 in FIG.
The first advance angle correction amount Δθ _T calculated in step 108 and the third advance angle correction amount Δθ _X calculated in step 202 are added to calculate the final advance angle correction amount Δθ (Δθ = Δθ _T
+ Δθ _X ). After that, the ECU 40 executes step 1 of FIG.
The final advance angle correction amount Δθ is output at 12, and the timer control valve 30
Drive.

FIG. 7 is a diagram showing the timing of the injection period. FIG. 7 (a) shows the case where the actual injection timing is ahead of the target injection timing, and FIG. 7 (b) shows the actual injection timing. It shows the case where it is behind the time. Also, FIG.
In (a) and (b), the solid line shows the target injection period, the broken line shows the actual injection period, the upper stage shows before correction, and the lower stage shows after correction. That is, in the case of FIG. 7A, when the central angle of the target injection period (solid line) is t1 and the central angle of the actual injection period (broken line) is t2, the injection timing is corrected so that t2 matches t1. It Further, in the case of FIG. 7B, when the central angle of the target injection period (solid line) is t3 and the central angle of the actual injection period (broken line) is t4, the injection timing is corrected so that t4 matches t3. It

As described above, also in the second embodiment, the object of the present invention can be achieved as in the first embodiment. In the configuration of the second embodiment, the barycentric position of the injection rate is directly obtained from the center of the target injection period and the center of the actual injection period, and the barycentric positions are made to coincide with each other. α (see table in Figure 4)
Need not be set.

The present invention can be embodied in the following modes other than the above embodiment. (1) In each of the above embodiments, as the actual injection timing detection means,
A needle valve lift sensor 35 that detects the needle valve lift of the fuel injection nozzle 34 is provided, and the actual injection timing is detected according to the detection result. However, a fuel pressure sensor that detects the fuel pressure fed to the fuel injection nozzle 34 is provided. Alternatively, the actual injection timing may be determined based on the detection result of the sensor.

(2) In the above embodiment, the face cam type fuel injection pump 1 is embodied, but it is also possible to embody the inner cam type fuel injection pump. (3) In each of the above-described embodiments, the diesel engine is embodied, but it may be embodied in another type of internal combustion engine for injecting and supplying high-pressure fuel.

[0049]

According to the invention described in claim 1, the excellent effect that the optimum combustion can be realized by appropriately performing the injection timing feedback control based on the characteristic of the injection rate is exhibited.

According to the second aspect of the invention, it is possible to realize appropriate correction based on the center of gravity position of the injection rate when the injection timing is corrected to the advance side or the delay side.

According to the third aspect of the invention, the change in the injection rate with respect to the engine operating state is reflected in the correction, and more appropriate injection timing control can be realized. According to the invention described in claim 4, it is possible to eliminate the deviation of the injection timing due to the individual difference such as an assembly error of the fuel injection pump.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an injection control device of a fuel injection pump for a diesel engine in an embodiment.

FIG. 2 is a flowchart showing a fuel injection timing control routine in the first embodiment.

FIG. 3 is a timing chart showing various signals related to fuel injection.

FIG. 4 is a table for calculating coefficients corresponding to load and engine speed.

5A and 5B are timing charts showing an injection rate curve in the first embodiment, where FIG. 5A shows a case where the actual injection timing shifts to the advance side, and FIG. 5B shows a case where the actual injection timing shifts to the delay side. Shows.

FIG. 6 is a flowchart showing a part of a fuel injection timing control routine in the second embodiment.

FIG. 7 is a timing chart showing an injection rate curve in the second embodiment, where (a) shows a case where the actual injection timing is shifted to the advance side, and (b) is a case where the actual injection timing is shifted to the delay side. Shows.

FIG. 8 is a timing chart for explaining a problem of the conventional technique.

FIG. 9 is a block diagram corresponding to a claim.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump, 25 ... Timer, 31 ... Rotation angle sensor as an actual reference angle detection means, 33 ... Engine (internal combustion engine), 34 ... Fuel injection nozzle, 35 ... Needle valve lift sensor as an actual injection timing detection means , 40 ... EC as actual injection timing detection means, target injection timing calculation means, injection timing correction means, injection timing control means, reference angle deviation amount calculation means
U.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Shinji, 1-1, Showamachi, Kariya city, Aichi Prefecture

Claims (4)

[Claims] 1. A fuel injection pump for sucking and pressurizing fuel according to the operation of an internal combustion engine to supply the pressurized high pressure fuel to a fuel injection nozzle, and an actual fuel injection timing by the fuel injection nozzle. Actual injection timing detection means for detecting, a timer provided in the fuel injection pump for adjusting the injection timing by the fuel injection pump, and a target injection timing calculation for calculating the target injection timing according to the engine operating state Means, the center of gravity position of the injection rate of the actual injection timing detected by the actual injection timing detecting means, and the center of gravity position of the injection rate of the target injection timing calculated by the target injection timing calculating means are matched, An injection timing correction means for correcting the target injection timing, and an injection timing control means for controlling the timer based on the injection timing corrected by the injection timing correction means are provided. Injection timing control device for a fuel injection pump to symptoms. 2. The fuel injection pump according to claim 1, wherein the injection timing correction means corrects an amount larger than a difference between the actual injection timing and the target injection timing if the actual injection timing is ahead or behind the target injection timing. Injection timing control device. 3. The injection timing correction means, the larger the operating load of the internal combustion engine or the smaller the engine speed,
The injection timing control device for a fuel injection pump according to claim 2, wherein the correction amount is increased in an excessive direction. 4. The injection timing control device for a fuel injection pump according to claim 1, wherein a pump reference angle with respect to a reference crank angle of the internal combustion engine is set in the fuel injection pump. An actual reference angle detecting means for detecting a pump reference angle, and a reference angle deviation amount calculating means for calculating a deviation between an actual pump reference angle by the actual reference angle detecting means and a preset target pump reference angle. The target injection timing calculation means calculates a target injection timing with respect to the pump reference angle, and the injection timing correction means includes the target injection timing according to the deviation amount of the pump reference angle calculated by the reference angle deviation amount calculation means. For controlling the injection timing of a fuel injection pump that corrects