JPS59173531A - Fuel injection timing adjusting device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To accurately detect an actual injection timing at all times irrespective of variation of a mount position of a detector, by displacing a driven member to a predetermined position upon starting of control operation of a control circuit, and setting a phase difference between a drive member and the driven member after displaced as a reference value. CONSTITUTION:An electric control circuit 5 serves to compute a target injection timing by a target injection timing setting means 6 on the basis of output signals from a drive sensor 2 and a load sensor 4, and further compute an actual injection timing by an actual injection time detector 7 on the basis of output signals from the drive sensor 2 and a driven sensor 3. Further, the control circuit 5 controls each of pressure control valves 9 and 10 by a pulse width setting means 8 according to difference between both the injection timings to drive an injection timing adjusting actuator 1'. A driven member of the actuator 1' is displaced to a predetermined position upon starting of control operation, and a phase difference between a drive member and the driven member as displaced is set as a reference value. Then, a phase difference as detected by both the detectors 2 and 3 is corrected according to the reference value, and the actual injection timing is computed on the basis of the corrected phase difference.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an actuator for controlling the fuel injection timing of an internal combustion engine.
This relates to a fuel injection timing adjustment device for an internal combustion engine that detects based on the phase difference between detection signals obtained from two detectors attached to a timer.

Conventionally, as in Japanese Patent Application Laid-Open No. 57-14.0530, a method of detecting fuel injection timing based on a phase difference between detection signals obtained from two detectors attached to an actuator for adjusting fuel injection timing, As shown in Fig. 1, for example, the pulse signal obtained by waveform shaping the signal from the driven side detector of the actuator is denoted as a, and the pulse signal obtained by waveform shaping the signal from the driving side detector is denoted by b. Based on the difference in the rising time of these pulse signals a and b, that is, the magnitude of the time t shown in FIG.
can be detected, and this time t and fuel injection timing θ
has the relationship shown in FIG.

However, with this type of device, the mounting of the driving side detector or the driven side detector may be due to positional errors, etc., so for example, if the phase difference t, which should originally be rl, becomes [1], the actual injection Even though the period θ=O, this is
It may be detected as a value that differs only when OFF is set.
Since the detected injection timing is different from the actual injection timing, there is a drawback that the fuel injection timing cannot be controlled correctly.

The present invention has been made in view of this point, and the mounting of the driving side detector or the driven side detector to the actuator depends on the position, the installation work, or the product variation of the detector. Even if the position is different from the intended position, that is, if there are variations between individual products and the detection signal does not match depending on the individual product, or if the detection signal is no longer accurate due to changes in the detector over time, etc., the actual injection will be performed correctly. The purpose of this is to detect the timing and optimize the fuel injection timing.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 8.

FIG. 2 is an overall configuration diagram of the device of the present invention, where 1 is a fuel injection pump, 1- is an actuator for adjusting the injection timing of the fuel injection pump 1, and is driven by hydraulic pressure, for example.
2 is an electromagnetic drive-side detector attached to the actuator 1', 3 is an electromagnetic driven-side detector also attached to the actuator 1', and 4 is a load for detecting the engine load. The detector 5 is an electrical control circuit, which is comprised of a target injection timing setting means 6, an actual injection timing detection means 7, and a pulse width setting means 8 for a pulse signal for driving the actuator 1'. Setting means 6
receives signals from the drive side detector 2 and the load detector 4,
The actual injection timing detecting means 7 receives signals from the driving side detector 2 and the driven side detector 3 to calculate the actual injection timing, and also calculates the actual injection timing according to the pulse signal. The pulse width setting means 8 controls the pressure control valve 9 of the actuator 1' according to the difference between the target injection period and the actual injection period.
．． A pulse signal for driving 10 is generated. The actuator 1' is driven in accordance with the oil pressure adjusted by driving the pressure horn control valve 9.10, and the injection timing of the fuel injection pump 1 is adjusted.

Next, FIG. 3 is a sectional view along the central axis showing the detailed structure of the hydraulic actuator 1'.A flange 13 is fixed to the fuel injection pump 1 by ports 1 to 12, and the A chamber 14 is provided, and a hydraulic piston 15 is made movable in the axial direction by the pressure of the fluid flowing into the hydraulic chamber 14.

The hydraulic piston 15 is provided with an inclined surface 16, and the axial surface 16
if shifters 17 that face each other and are in contact with each other and are slidable in the radial direction.
is arranged, and the shifter 17 is connected to the eccentric shaft pin 18 of the eccentric cam.
Since the small eccentric cam 20 is rotated by the radial movement of the shifter 17, the eccentric cam 1
It is configured such that the phase of the hub 22 (driven member) housing the two can be changed. On the other hand, the hub 2
The outer circumferential portion 23 of 2 and the saw bar 24 (a component of the driving member) are rotatably fitted, and the cover 24 is fixed with bolts 26 to the -Land cover 25 in which the driving bin 21 is installed. , and the end cover 25.

In the above configuration, drive-side uneven portions 27 are formed at equal intervals on the outer circumference of the cover 24, which is a drive-side rotating member that rotates integrally with the drive shaft of the engine, and the flange 13 is further provided with poles 1-1.
A bracket 29 fixed at 28 is arranged, and the bracket 2
The electromagnetic drive-side detector 2 is screwed into the drive-side detector 9 and faces the drive-side uneven portion 27 . Further, the two brackets have elongated holes in the flange 13 that are movable along the direction of rotation of the cover 24.

Also, the fuel injection cam on the driven side? Ill 30 and key 3
The hub 22 , which constitutes a driven rotating member positioned by 1, has the same number of driven side uneven parts 32 as the driving side uneven parts 27 of the cover 24 , and an electromagnetic driven side that is screwed onto the flange 13 . It is made to face the detector 3.

Next, FIG. 4 is a diagram showing details of the electrical control circuit 5 shown in FIG. A waveform that is easy to handle for the microcomputer 34 (Fig.
a, b) and input into the microcomputer 34. 35 is a rack position detector, and the load detector 4
, the engine load is detected at the rack position of the fuel injection pump 1, 36 is an oscillation drive circuit for driving the rack position detector 35, and 37 is an oscillation drive circuit for driving the rack position detector 35. A detection circuit 38 for detecting a signal and generating a DC voltage corresponding to the rack position;
The ID conversion circuit converts the analog signal from the detection circuit 37 into a digital signal and inputs it to the microcomputer 34. Also, the microcomputer 34 has an internal RO
A drive circuit 39 which is connected to the output of the microcomputer 34 and includes M, RAM, and timer i functions.
micro:]] The signal from Hibi-1-93 is current amplified to drive the pressure control valve 9.10. The pressure control valves 9 and 10 are provided one each on the oil inflow side and oil outflow side, and the oil pressure is adjusted by controlling the opening time of each valve based on the output signal of the microcomputer 34, and the oil pressure is injected. This is to control the timing.

Next, the operation of the microcomputer 34 will be explained based on the flowchart of FIG.
The memory, input/output board, etc. inside the computer are reset to their initial state. Next, in step 101, the mounting position of the drive side detector 2 is detected and this value is stored. In step 102, the engine rotation speed is calculated based on the data obtained in steps 108 to 109 of the interrupt routine shown in FIG. 6, and in step 103, a rack position signal is input through the A/D conversion circuit 38, In step 104, the engine speed obtained in step 102 and step 103 are
The target injection timing is calculated based on the rack position determined by 151. Step 105 calculates the actual injection timing based on the value obtained in step 101 and the value obtained in the interrupt routine shown in FIG. A comparison is made with the obtained actual injection timing, and according to this difference, the pulse width of the drive signal to the pressure control valves 9.10 on the inflow and outflow sides of the hydraulic pressure is calculated, and in steps 10 and 7, step 106 Output the pulse signal with the pulse width calculated in step 102 to the drive circuit 39, and then return to step 102 again.
Repeat steps 102-107.

When executing the process shown in Figure 1,
, b is input to the microcomputer 34, and when the computer detects the rising edge of this pulse,
The program moves to the interrupt routine shown in FIG. In the core injection routine, in step 108, the value of the free-run timer built into the computer is read, and the value of the free-run timer is incremented by "1" at a constant period.In the next step 109, this interrupt is Determine whether the routine is activated by the rising edge of signal a or the rising edge of signal A shown in FIG. , is stored in a memory address that can be accessed south depending on the case, and after the above processing is executed, the process moves to the main routine and normal processing is performed.

Next, FIG. 7 shows in detail the execution content of step 101 shown in FIG. Set the oil pressure to O. Actuator J-Y mechanically sets injection timing θ-〇0 at oil pressure O.
becomes. In step 202, the rise time difference 1 between the signal a from the driven side detector 3 and the signal S from the driving side detector 2 shown in FIG. Check whether it is larger than the set Twn~ and smaller than TM'4y.
If this is Tyt~<j<TingMAX, step 20
If not, the process returns to step 202.

This tolerance range is determined when the detector 2.3 is normally installed and satisfies the conditions when fully retarded. This is to prevent an incorrect phase force from being stored as a fixed value in the case of tp.
What should I do with the OS?

Next, FIG. 8 shows in detail the execution content of step 105 in FIG.
The correct time difference Tp is determined by measuring the difference t between the rise times of the pulses and the signal pulses, and then subtracting the value of the lower PoS obtained in step 101 from the value of the time difference t measured in step 301 in step 302. Calculate. next,
In step 303, the actual injection timing θp is calculated from this value Tp and the engine speed N.

Next, the operation of the fuel injection timing adjustment device described above will be explained.

Now, the engine speed is N+(rl)m) and the rack position is 1.
[It is assumed that the engine is in operation at step 1, and the injection timing at that time is θ°.
Suppose it was. A sine wave with a frequency proportional to the rotation speed N1 is input from the drive side detector 2 to the waveform shaping circuit 33,
Pulse train with a frequency proportional to the rotation speed N1 (Fig. 1 - [)
) and input to the Δ terminal of the microcomputer 34. On the other hand, the pulse train (Fig. 1-a) obtained by passing the output of the driven side detector 3 through the waveform shaping circuit 33 has a frequency equal to that of the rotation speed detector, and a time difference t according to the injection timing θ°. This pulse train is input to the B terminal of the fibrocomputer 34. Then, the microcomputer 371 executes the interrupt routine shown in FIG. 6 by the pulse sent to the A terminal, reads the value T1 of the free run timer, and since it is input to the A terminal, this value T
1 is stored in the AnW location (rotation speed data memory address) of the memory, and then the process moves to the main routine. Also, when a pulse is input from the B terminal after a delay of time 1, the interrupt routine starts, reads Iil'j T 2 of the free-run timer, and this time, since the input is from the B tm child, its (
After storing a T 2 in the memory address Bn (injection timing data memory address), return to the main routine, and then when a pulse is input to the AGiAf element again, the free run timer value T3 at that time is stored in the Ann address. . The processing of the main routine is repeated until the step of the interrupt routine ends and the next interrupt occurs. Step 10
2, read data T+, , Ta from rotation speed data memory address A n XAnu, and set 1 / (Ta
-T1) K1: Calculate constant and obtain rotation speed data.

Next, in step 103, the rack position data R1 is read from the A/D converter 38, and in step 104, a map search and four-point interpolation are performed from the data N1 and R1 to calculate the target injection timing t1''. Next, in step 105,
Read data T2 and T1 from injection timing data memory address [3n and rotation speed data address 〇, calculate j 1=T+ -T2, and then use the value t1 obtained by this calculation and the value obtained in step 101 above. From the time difference Tpos at the injection timing θ-〇0CAM, t1''-11-tp
oS is calculated and used as actual injection timing data.

In steps 106 and 107, tl'' and tl - are compared, and Δt'=t, ``-11-'' is calculated as the error time. If Δ[>0, then an output signal is output to the drive circuit 39 so that the hydraulic actuator operates in the direction of increasing the angle, and if Δ[<Q, the hydraulic actuator operates in the direction of advancing the angle.

By repeating the above, the adjustment is always repeated to achieve the optimum injection timing. Even if it is, the correct injection timing is always detected by memorizing the position (t4) in advance in step 101 and performing processing using this value in step 105. It becomes possible to
The correct injection timing can be adjusted over a long period of time. Further, even if the phase of the hydraulic actuator 1 sometimes varies in the mounting position of the detector, the injection timing can always be adjusted correctly.

As described above, the present invention comprises an actuator that determines the relative position of a driven member with respect to a driving member, a driven-side detector that detects the position of the driven member, and a position of the driven member. and a drive-side detector that detects the target injection timing, and detects the actual injection timing based on the phase difference between the two members 1F detected by both the detectors, and sets the target injection timing. In the fuel injection timing adjustment device for an internal combustion engine, the device includes a control circuit that corrects a drive signal accordingly and outputs it to the actuator, which displaces the driven member to a predetermined position when control by the control circuit starts, and after the displacement. Means for setting the phase difference between the two members as a reference value, then correcting the phase difference in the side detector using the reference value, and detecting the actual injection timing based on the corrected phase difference. A fuel injection timing adjustment device for an internal combustion engine, characterized in that the control circuit is provided with:

This has the effect that the actual injection timing of the fuel injection device can always be accurately detected regardless of variations in the mounting position of the detector or changes over time.

In addition, there is no need to precisely adjust the position of the detector as in the conventional method, and the detector can be easily installed at a preset position with an allowable width within the correction range1-). It is effective to significantly reduce the number of man-hours required for installing the detector.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a graph showing the relationship between the signal waveform of the detector, injection timing, and phase difference, Fig. 2 is an overall configuration diagram, and Fig. 3 is a graph showing the relationship between the signal waveform of the detector and the injection timing and phase difference. is a block diagram of the actuator, Fig. 4 is a 1 [ ] diagram of the electrical control circuit, and Fig. 5 is a block diagram of the electric control circuit.
8 through 8 are flowcharts showing the execution program of the microcomputer. 1...Actuator 2...Drive side detector 3
...Driven side detector 4...Load detector 5...
- Electrical control circuit 9.10... Pressure control valve 22... Driven member 24
...An example of a drive member (cover 33, which is a component of the circuit)...Waveform shaping circuit 34...Microcomputer 39...Drive circuit '- Agent: Patent attorney Tsutomu Ashikari et al. No. 5 Figure Figure 6-181-

Claims (1)

[Scope of Claims] 1. An actuator that determines the relative position of the driven member with respect to the driving member, a driven side detector that detects the position of the driven member, and a driving side that detects the position of the driving member. A detector and a target injection timing are set, and the actual injection timing is detected based on the phase difference between the two members detected by both the detectors, and the drive signal is corrected according to the difference between the two injection timings. , a fuel injection timing adjustment device for an internal combustion engine comprising a control circuit that outputs output to the actuator, which displaces the driven member to a predetermined position when the control circuit starts control, and adjusts the position between the two members after the displacement. The control circuit is provided with means for setting the phase difference as a reference value, then correcting the phase difference detected by the rain detector using the reference value, and detecting the actual injection timing based on the corrected phase difference. Fuel injection timing adjustment device for internal combustion engines. 2. The fuel injection timing adjustment device for an internal combustion engine according to claim 1, wherein both of the members are rotating members, and each of the detectors detects rotation of the rotating member.