JP3008136B2 - Electronic fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled fuel injection device for controlling a fuel injection pump based on a signal from a control unit.

[0002]

2. Description of the Related Art A fuel injection pump used in this type of fuel injection device has an adjusting member for adjusting a fuel injection amount in a pump body, and the adjusting member is operated by an actuator operated by a control signal from a control unit. It is supposed to.

When the control unit calculates the target position of the adjusting member according to the engine conditions, the drive amount of the actuator corresponding to the target position is determined. The actuator is attached to the pump body by bolts or the like. If the mounting accuracy to the pump body is poor, the intended injection amount cannot be obtained.

Therefore, when assembling the fuel injection pump,
It is necessary to perform an operation of shifting the relative position between the actuator and the pump body in a state where the mounting bolts of the actuator are loosened, and performing positioning so as to obtain a predetermined injection amount characteristic.

[0005] It takes a considerable amount of time and effort to accurately mount the actuator, which hinders mass production of the fuel injection pump. Therefore, conventionally, the actuator is positioned within a certain accuracy range. After installation, the pump tester measures the deviation of the actual injection amount from the reference injection amount when the fuel injection pump reaches the predetermined number of revolutions, and converts the information corresponding to this deviation into a resistance value and possesses it. It should be noted that the applicant has considered that the target injection amount is corrected based on the resistance value when controlling the fuel injection pump.

For example, assuming that the target reference injection amount is Q1 and the actual injection amount is Q2 smaller than Q1 for a certain rotational speed NA in FIG. 10, the target injection amount is (Q1-Q2) with respect to Q1. ) Is added to Q3, and the actual injection amount is controlled so as to approach Q1.

[0007]

However, in actual control, the target injection amount is converted into the target position of the adjusting member based on the conversion map stored in the control unit, and the actuator is controlled based on the target position. The drive amount of the actuator is controlled while detecting the actual drive position.

The conversion map for converting the injection amount into the position of the adjusting member takes into account the non-linear characteristics between the engine speed and the injection amount, and obtains the optimum position for each target injection amount with respect to the standard injection pump. Has been decided to be
If the correction based on the displacement of the actuator is corrected by shifting the target injection amount itself as described above, the target position converted by the conversion map is shifted from the position at which the original optimum injection amount is obtained at each position where the position is converted.

In this case, there is an inconvenience that satisfactory correction cannot be performed, although it was originally intended to correct the displacement of the actuator with high accuracy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electronic fuel injection device which can solve the above-mentioned inconveniences and accurately correct an assembly error of an actuator unique to each fuel injection pump.

[0011]

SUMMARY OF THE INVENTION Accordingly, the gist of the present invention is that, as shown in FIG. 1, an adjusting member for adjusting the fuel injection amount is provided in the pump body, and the adjusting member is provided with the adjusting member.
A fuel injection pump 1 for controlling the position of the fuel injection pump by an actuator mounted on the pump body, a control unit 22 provided independently of the fuel injection pump 1 for controlling the actuator, and a predetermined rotation of the fuel injection pump 1 A correction element 29 attached to the fuel injection pump 1 having a correction amount determined in accordance with a deviation of the injection amount from the reference injection amount in the number as a predetermined physical quantity, and the fuel injection pump 1 Target injection amount calculating means 100 for calculating the target injection amount, target position calculating means 200 for converting the target injection amount calculated by the target injection amount calculating means 100 to a target position of the adjusting member, and the target position calculation Correction means 300 for correcting the target position calculated by the means 200 based on the physical quantity of the correction element
Position detection for detecting the actual driving position of the actuator.
Output sensor 21 and a signal from the position detection sensor 21.
While being fed back, the correction
To adjust the position of the adjusting member to the target position.
Drive control means 400 for driving and controlling the actuator;
To have.

[0012]

Therefore, when the target injection amount is calculated by the target injection amount calculating means, the target injection amount is converted to the target position of the adjusting member by the target position calculating means, and thereafter, the target position of the adjusting member is corrected by the correcting means. It is corrected to a position which satisfies a correlation property between the adjusting member and the injection quantity to be originally obtained, the correction of
To adjust the position of the adjustment member to the target position
Feedback control is performed.

The manner of this correction will be described with reference to FIG. 10. For a certain rotational speed NA, the target reference injection amount is Q1, and the actual injection amount is smaller than Q1 due to an assembly error of the actuator. If it is a small Q2,
The target position corresponding to the target injection amount by the correction means is Q1
Is corrected from the position where the injection amount is obtained to the position where the injection amount of Q2 is obtained.

Therefore, the deviation from the reference characteristic due to the assembly of the actuator is not dealt with by correcting the target injection amount itself, but by correcting the target position of the adjusting member. In the conversion process, there is no possibility that the target position deviates from the position where the original optimum injection amount is obtained. Moreover, depending on the target injection amount itself,
Target the position of the adjustment member instead of controlling the injection quantity
Feedback control to control the injection amount
Therefore, control accuracy can be improved.

[0015]

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

FIG. 2 shows a part of the fuel injection pump 1, and the fuel injection pump 1 has an actuator 3 called an electric governor (GE) attached to a pump body 2.

The pump body 2 has a plunger 5 slidably mounted on a plunger barrel 4, and the plunger 5 connects a cam disk 6 fixed to a base of the plunger 5 with a drive shaft 7. By rotating, the reciprocating movement for suction and pressure feeding of the fuel and the rotation for distributing the fuel are simultaneously performed.

In the suction step in which the plunger 5 moves to the left in the drawing, fuel supplied from the oil feed pump to the chamber 8 passes from the suction port 9 through one of the suction grooves 10 formed in the axial direction of the distal end of the plunger 5. The suction port 9 and the suction groove 10 are separated from each other and are compressed in the pump chamber 11 at the time of the pumping process in which the plunger 5 moves rightward in FIG. The fuel is plunger 5
After passing through 2 from the distribution port 13 to one of the distribution passages 14, it is sent to the injection nozzle via the delivery valve 15, and is injected into the cylinder of the engine.

The plunger barrel 4 of the plunger 5
When the control sleeve 16 is slidably fitted to the portion protruding from the outside, and the cutoff port 17 communicating with the vertical hole 12 of the plunger 5 is released from the upper edge of the control sleeve 16 and opens into the chamber 8, it is compressed. Since the discharged fuel flows into the chamber 8, the delivery to the injection nozzle is stopped, and the injection ends. Therefore, the injection end, that is, the injection amount can be adjusted by adjusting the position of the control sleeve 16, and the injection amount can be reduced as the control sleeve 16 is moved to the left in the drawing.

A ball 20 at the tip of a shaft 19 mounted on the rotor 18 of the actuator 3 is engaged with the control sleeve 16. This ball 20
The control sleeve 16 is provided eccentrically with respect to the shaft 19 and can move the control sleeve 16 in the axial direction of the plunger 5 according to the rotation angle of the rotor 18.

Above the actuator 3, a position detecting sensor 2 for detecting the position of the control sleeve 16, that is, the rotation angle of the rotor 18 (actual driving position of the actuator).
1 is provided, and an actual position signal P from the position detection sensor 21 is sent to the control unit 22.

The control unit 22 is connected to the injection pump via a connector, and includes a drive circuit for driving the actuator 3, a microcomputer for controlling the drive circuit, an input circuit for inputting signals to the microcomputer, and the like. The input circuit of the control unit 22 includes the position detection sensor 2
In addition to the signal from No. 1, an engine rotation speed N, an accelerator position signal AC indicating the amount of depression of an accelerator pedal, a water temperature signal TW indicating the temperature of engine cooling water, a fuel temperature signal TF indicating the temperature of fuel, and the like are input. , And processes these signals to drive and control the actuator 3.

FIG. 2 shows only the main part that controls the injection of the injection pump, but other structures are omitted because they are not different from the conventional pump.

Next, the assembling adjustment of the actuator of the injection pump will be described with reference to the flowchart of FIG.

First, an actuator (G) is attached to the pump body 2.
E) Temporarily fix the 3 with bolts or the like and assemble it (Step 50), energize the GE, and set the rotation angle of the rotor 18 to a predetermined adjustment point (Step 51).

Then, air pressure is applied to the plunger 5,
The flow rate at the adjustment point is measured, and the GE mounting position is relatively shifted with respect to the pump body 2 so as to match this flow rate with a predetermined reference flow rate (step 52). Then, the actuator 3 is fixed (step 53).

Since the above-described position adjustment uses air pressure instead of fuel, strict accuracy cannot be obtained, but is a rough adjustment for securing a certain degree of accuracy. In order to perform highly accurate position adjustment, the mounting position of the GE may be finely adjusted so that the actual injection amount matches the reference injection amount under predetermined conditions. However, since a great deal of labor is required, the following adjustment steps are required. Is adopted.

First, the injection pump 1 is rotated at a predetermined rotation speed using a pump tester, the rotation angle of the rotor 18 is set to a predetermined adjustment point, and the actual fuel injection amount Qa at that time is set.
Is measured (step 54).

Then, the reference injection amount Q at the adjustment point
Select obtains a deviation (ΔQ = Qa-Q _N) of the actual injection quantity Qa from _N, an adjustment resistor (Q adjustment resistor) having a resistance value associated in advance in accordance with the magnitude of this deviation Delta] Q from Table 1 Then, the Q-adjustment resistor is attached to the injection pump 1 (step 56).

Since the actuator 2 is assembled with a certain degree of accuracy in the rough adjustment in the previous stage, the injection amount Q is substantially proportional to the converted voltage (Uα _ist ) of the sleeve position for a minute section required for fine adjustment. (FIG. 4), based on the characteristics of ΔQ and ΔUα _ist , the Q adjustment resistance is associated with ΔQ.

[0031] In this example, 9 stages with respect to the deviation from Delta] Q is _{Q N (ΔQ A, ΔQ B} , ΔQ C, Δ
_{Q D, 0, ΔQ E,} ΔQ F, ΔQ G, divided into ΔQ _H), Q adjustment resistor nine stages corresponding thereto (RA, RB, R
C, RD, RN, RE, RF, RG, RH), and any one of them is selected. As a more specific example, ΔQ is １ ／ (ΔQ _G + Δ
Q _F ) and _F (ΔQ _G + ΔQ _H ), RG is selected, and in another example, ΔQ is （(ΔQ _G + ΔQ _H ).
RN is selected when it is between _D ) and 1/2 (ΔQ _E ).

[0032]

[Table 1]

The attachment of the Q-adjustment resistor to the injection pump 1 is performed, for example, as shown in FIG.
Then, a resistor mounting connector 28 is connected to the harness via a lead wire 26 fixed to a band 25, and a Q-adjustment resistor 29 is fitted to the resistor mounting connector 28.

Next, an operation example in which the control unit 21 controls the injection pump 1 in which the assembly adjustment of the actuator 3 has been completed will be described.

In FIG. 6, the control unit 22
The general processing of is shown, the control unit 22
Initialized when the ignition is turned on (step 5
8) After that, various background jobs (BGJ)
Is repeatedly performed (step 59). In the process, a predetermined pulse (TD) generated with the rotation of the engine
The fuel injection control shown in the flowchart of FIG. 7 is executed by interruption C).

This flowchart will be described with reference to the functional block diagram of the fuel injection control shown in FIG. 8. First, at step 60, the target injection amount is calculated as follows.

The control unit 22 calculates the traveling injection amount (drive Q) from the injection amount characteristic during normal traveling stored in advance in the ROM as map data based on the engine speed N and the accelerator position signal AC,
Also, based on the parameters representing the state change during idling (engine speed N, engine coolant temperature TW, battery voltage VB, air conditioner switch ON / OFF),
An idling injection amount (idle Q) for keeping the target idling speed constant with respect to the load fluctuation during idling is calculated.

The idle Q is adjusted in consideration of the variation of the injection amount for each cylinder, and is added to the drive Q when the engine speed is lower than the predetermined speed (position A). If the speed is equal to or higher than the predetermined speed, it is not added to the drive Q (position B).

Further, based on the engine speed N and the like, the maximum injection quantity (full Q) allowed on the engine performance
Is calculated from the characteristic data shown in FIG. 10, this full Q is compared with the target injection amount obtained up to the previous stage, and the smaller one is selected so that the target injection amount does not exceed the full Q. I do.

The above target injection amount is applied in the normal running mode (D position). In the initial stage of starting, a target injection amount with good startability is determined based on the engine speed N and the engine coolant temperature TW. (C position). Further, when the engine rotation speed N is 0 or when there is an abnormality, the target injection amount is not calculated (position E).

After the target injection amount (Q _SOL ) is calculated,
In step 61, calculation processing of fuel temperature correction is performed. This fuel temperature correction is to correct the target injection amount based on the engine speed N and the fuel temperature TF, since the actual injection amount decreases with a decrease in the fuel density due to an increase in the fuel temperature. Proceeding to step 62, the target injection amount is converted into a control sleeve target position signal.

This target position signal is corrected (Q adjustment) based on the Q adjustment resistance attached to the fuel pump in the next step 63, and then output to the drive circuit in step 64 (F position). ), When the engine rotation speed N is 0 or when there is an abnormality, no output is made (G position). Then, the drive circuit supplies the current I to the actuator so that the actual position of the control sleeve 16 becomes the corrected target position while feeding back the signal P from the position detection sensor, and the rotation angle of the rotor 18 is adjusted. Control.

The Q adjustment will be described in detail with reference to the flowchart of FIG. 9. First, in step 65, the amount of deviation (ΔUα _ist ) of the sleeve position voltage from the reference position voltage from the Q adjustment resistor attached in the adjustment stage. Is read out from the ROM data (ΔU) corresponding to. This data is obtained by assigning the median (128) of the full range from 0 to 255 to R _N, and assigning the values before and after R _N to R _A to R as shown in Table 1 above.
_The control unit 22 applies a predetermined voltage to the Q-adjustment resistor 29 and determines the magnitude of the Q-adjustment resistor from the amount of current flowing through the Q-adjustment resistor 29. After reading the corresponding numerical data from the ROM, the process proceeds to step 66.

In step 66, Δ from 128
The deviation of U, that is, the correction value (ΔU _RQ ) of the position signal of the control sleeve is calculated, and in the next step 67,
The target position signal is corrected by adding ΔU _RQ to Uα _ist .

For this reason, when correcting the target injection amount itself, feedback control is not performed using the actual injection amount at the time of pump control, but the actual injection amount region (the region based on the engine rotational speed and the load) is not actually controlled. Because the relationship between the injection amount and the position of the adjustment member does not have linearity, it is difficult to completely match the actual injection amount to the reference characteristic in the entire injection amount control region.
When correcting the target position signal, feedback control can be performed in accordance with the output of the position sensor (sleeve position), so that direct correction is possible in the entire injection amount control region, and the actual injection amount can be easily adjusted to the reference characteristic. They can be matched exactly.

[0046]

As described above, according to the present invention,
The target injection amount calculated by the control unit is converted into a target position of the adjustment member, and then the target position is corrected to a position that satisfies the correlation characteristic between the adjustment member and the injection amount that is originally desired. Adjust the position of the adjustment member to
Since the feedback control is performed so as to match, it is possible to accurately correct the deviation of the injection characteristics due to an assembly error of the actuator of the fuel injection pump.

Further, it takes a lot of time and effort to finely adjust the relative position between the actuator and the pump body to obtain the predetermined injection characteristics. However, according to the present invention, the deviation from the reference characteristics is required. Since it is only necessary to attach a correction element corresponding to the above, it is not necessary to assemble the actuator and the pump body with high accuracy, and the number of assembling adjustment steps can be greatly reduced.

Further, since the correction element is attached to the fuel injection pump itself, the assembly error of the actuator is corrected by the pump itself, and readjustment is performed even when the fuel injection pump is replaced with the control unit. Some benefits are unnecessary.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an electronic fuel injection device of the present invention.

FIG. 2 is a schematic configuration diagram showing an embodiment of an electronic fuel injection device.

FIG. 3 is a flowchart showing a procedure for adjusting the assembly of the actuator of the fuel injection pump.

FIG. 4 is a characteristic diagram showing a relationship between a deviation of an actual injection amount from a reference injection amount and a deviation of a sleeve position voltage from a reference position voltage.

FIG. 5 is a diagram showing a structure near a connector of the fuel injection pump.

FIG. 6 is a flowchart showing general processing of the control unit.

FIG. 7 is a flowchart showing an operation example of the injection amount control of the control unit.

FIG. 8 is a functional block diagram showing an operation example of injection amount control.

FIG. 9 is a flowchart illustrating a processing example of Q adjustment in FIGS. 7 and 8;

FIG. 10 is a diagram showing characteristics of a maximum injection amount (full Q) allowed in engine performance.

[Explanation of symbols]

 Reference Signs List 16 control sleeve 1 fuel injection pump 2 pump body 3 actuator 22 control unit 29 Q adjustment resistance (correction element) 100 target injection amount calculation means 200 target position calculation means 300 correction means 400 drive control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02D 41/40

Claims (1)

(57) [Claims] 1. A fuel injection pump having an adjustment member for adjusting a fuel injection amount in a pump main body, wherein a position of the adjustment member is controlled by an actuator mounted on the pump main body, and independently of the fuel injection pump. A control unit provided to control the actuator; and a correction amount determined in accordance with a deviation of an injection amount from a reference injection amount at a predetermined rotation speed of the fuel injection pump as a predetermined physical amount. A correction element attached to the fuel injection pump, a target injection amount calculating means for calculating a target injection amount of the fuel injection pump corresponding to engine conditions, and a target injection amount calculated by the target injection amount calculation means as a target position of the adjusting member. A target position calculating unit that converts the target position into a target position, and correcting the target position calculated by the target position calculating unit based on a physical quantity of the correction element. Position detection cell for detecting and correcting means, the actual drive position of said actuator
And feed back the signal from the position detection sensor.
The adjusting member is moved to the target position corrected by the correction means.
Drive control of the actuator to match the position of
An electronic fuel injection device, comprising: