JP2524788B2 - Sequence type fuel injection timing control device for diesel engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sequence type fuel injection timing control device for a diesel engine, and more specifically, an injection timing calculation based on a rotation speed detection signal of a rotation speed sensor of a diesel engine. Sequence of a diesel engine configured so that the device calculates a target value for fuel injection timing control, controls and drives a stepping motor, and controls the fuel injection timing adjuster in advance according to the value of the rotation speed detection signal. Type fuel injection timing control device.

<Prior Art> As a conventional sequence type fuel injection timing control device for a diesel engine as described above, the one shown in FIG. 8 is known. In the sequence type fuel injection timing control device of FIG. 8, a ring gear 8 is provided on a flywheel 14 that is interlocked with the crankshaft of the engine E, and a rotational speed sensor 1 is attached to this ring gear 8. Further, a fuel injection nozzle 16 is provided in the cylinder head 15 of the engine E, and the fuel injection pump 10 is connected to the fuel injection nozzle 16. Further, the fuel injection pump 10 is provided with a fuel injection timing adjusting tool 4, and the fuel injection timing adjusting tool 4 uses the stepping motor 3
The advance angle control operation is performed by (operation shown by a two-dot chain line in FIG. 8). Further, the rotation speed detection signal of the rotation speed sensor 1 is configured to be input to the injection timing calculation device 40 which is a microcomputer, and for the fuel injection timing control calculated by the injection timing control calculation unit 41 of the fuel timing calculation device 40. It is configured to supply an advance control current to the stepping motor 3 based on the target value.

In the sequence type fuel injection timing control device 40,
When the stepping motor 3 has an initial deviation (zero adjustment failure), accurate advance control cannot be performed based on the fuel injection timing control target value calculated by the injection timing control calculation unit 41. In order to correct the initial deviation of the stepping motor 3, a method is known in which the stepping motor 3 is fed in one direction before the engine is started, and zero adjustment is performed at the origin position of the stepping motor 3 (hereinafter referred to as Conventional Example 1). Called).

Further, in JP-A-53-105639, the deviation from the true zero position of the engine load detection sensor when the power is turned on, that is, the offset amount is automatically measured and stored, and the offset amount is subtracted from the value of the subsequent sensor to obtain the true value. Has proposed an electronic advance device for an internal combustion engine, which detects the engine load and controls the advance. By using the concept of this device, the initial deviation of the stepping motor 3 is detected in advance as an offset amount, and the fuel injection timing control target value obtained by subtracting the offset amount is calculated by the injection timing control calculation unit 41. With such a configuration, it is possible to correct the initial deviation (hereinafter referred to as Conventional Example 2).

In this manner, the initial deviation of the stepping motor 3 can be corrected by the method of the above-mentioned Conventional Example 1 or Conventional Example 2.

<Problems to be Solved by the Invention> However, when the stepping motor 3 is displaced due to some disturbance element during the operation of the engine E instead of the initial displacement (hereinafter, the displacement in such a case is referred to as an operation displacement). However, it cannot be solved by the methods of the first embodiment and the second conventional example. Such misalignment of the stepping motor 3 may be a misalignment of the stepping motor 3 itself, or a relative misalignment between the stepping motor 3 and the fuel injection timing adjusting tool 4. To be

More specifically, the methods of Conventional Example 1 and Conventional Example 2 are for correcting the initial deviation in zero adjustment to the last. Therefore, when the operation deviation occurs in the sequence type apparatus which is the open loop control, the operation is performed. Data concerning the amount of deviation cannot be detected, and it becomes impossible to correct the operation deviation. In addition, it is sufficiently conceivable that the operation deviation of the stepping motor 3 occurs a plurality of times during the operation of the engine. In that case, the operation deviation of the stepping motor 3 is accumulated, so that the deviation width is further increased. Even if the injection timing control calculation unit 41 accurately calculates the fuel injection timing control target value, appropriate advance angle control cannot be performed.

A first object of the present invention is to automatically correct the operation deviation during the operation of the engine E even when the operation deviation occurs in the stepping motor due to some disturbance element during the operation of the engine, and to appropriately adjust the advance angle. It is an object of the present invention to provide a sequence type fuel injection timing control device for a diesel engine that can perform control.

A second object of the present invention is to provide a diesel engine capable of promptly correcting an operation deviation and performing an appropriate advance control regardless of whether the engine is operated near the idle speed or near the rated speed. It is to provide a sequence type fuel injection timing control device.

<Means for Solving the Problems> A sequence type fuel injection timing control device for a diesel engine of the present invention will be described with reference to, for example, FIGS. 1 to 4, the rotation speed of a rotation speed sensor 1 of a diesel engine E. Based on the detection signal, the injection timing calculation device 2 calculates a target value for fuel injection timing control, and controls the stepping motor 3 to drive the stepping motor 3 according to the target value.
In a sequence type fuel injection timing control device for a diesel engine configured to perform advance control operation of the fuel injection timing control device 4 driven by, in accordance with the value of the rotation speed detection signal, the maximum fuel injection timing control device 4 is used. An advance angle limiter 5 that receives the advance angle position A and the minimum advance angle position B is provided at each position, and the injection timing calculation device 2 includes an injection timing control calculation means 6 and a control position deviation calibration calculation means 7. , The low speed side control position deviation calibration rotation range C ₁ is set near the idle speed of the diesel engine E, and the high speed side control position deviation correction rotation range C ₂ is set near the rated speed. 2 in response to detecting that the value of the rotation speed detection signal of the rotation speed sensor 1 is within the injection timing control rotation range D outside the control position deviation calibration rotation ranges C ₁ and C _2. Timing control Calculating means 6 the maximum advanced position A
To a minimum advance angle position B, a target value for fuel injection timing control is calculated to an appropriate advance angle control value corresponding to the value of the rotation speed signal detection, and the stepping motor 3 is appropriately controlled and driven to inject fuel. The timing adjuster 4 is configured to perform an advance control operation corresponding to the value of the rotation speed detection signal, and the injection timing calculation device 2 causes the value of the rotation speed detection signal of the rotation speed sensor 1 to be the rotation for calibration of the control position deviation. In response to the detection of the state in the regions C ₁ and C ₂ , the control position deviation calibration calculation means 7 advances the fuel injection timing control target value to the maximum value in the high speed side control position deviation calibration rotation range C _2. Calculated as an excessive advance value h higher than the angle value a, and the low-speed side control position deviation calibration rotation range
At C ₁ , the target value for fuel injection timing control is calculated to be an excessive retard value 1 lower than the minimum advance value b, and the stepping motors 3 are excessively controlled and driven, and the fuel injection timing adjuster 4 is advanced to the maximum advance angle. It is characterized in that a calibration operation is performed up to each of the position A and the minimum advance angle position B so that the advance angle restrictor 5 receives the correction operation.

<Operation> According to the present invention, by providing the advance angle restrictor 5, when the fuel injection timing control target value deviates in the direction exceeding the maximum advance position A or the minimum advance position B due to the operation deviation, The fuel injection timing adjuster 4 is received at the maximum advance position A or the minimum advance position B. Therefore, in that case, the target value for fuel injection timing control that exceeds the maximum advance position A or the minimum advance position B is the stepping motor 3
Since the stepping motor 3 cannot move in accordance with the target value even if it is input to, the maximum advance position A received by the stepping motor 3 or the minimum advance angle position A received by the stepping motor 3 even if the operation deviation occurs When returning from the advance position B in the opposite direction, it is possible to correct the operation difference by using the target value corresponding to the maximum advance position A or the minimum advance position B as a reference.

On the other hand, when the fuel injection timing control target value deviates in the direction that does not exceed the maximum advance position A or the minimum advance position B due to the operation deviation, the fuel injection timing adjuster 4 causes the maximum advance position A or the minimum advance position A to be exceeded. It is not received at the angular position B, the operation deviation of the stepping motor 3 cannot be corrected, and the advance angle control is performed with the deviation.

Therefore, in the device of the present invention, the control position deviation calibration rotation ranges C ₁ and C ₂ are set both near the engine idle speed and near the rated speed, and the injection timing calculation device 2 causes the rotation speed sensor 1 to operate. In response to the detection of the state in which the value of the rotation speed detection signal of the control position deviation calibration is within the control position deviation calibration rotation range C ₁ or C ₂ , the control position deviation calibration calculation means 7 is used for the high speed side control position deviation calibration. In the rotation range C ₂ , the fuel injection timing control target value is calculated to be an excessive advance value h higher than the maximum advance value a, and in the low speed side control position deviation calibration rotation range C ₁ , the fuel injection timing control target value is calculated. Excessive retardation value l lower than the minimum advance value b
Then, the stepping motor 3 is excessively controlled and driven, and the fuel injection timing adjusting tool 4 is calibrated to the maximum advance position A and the minimum advance position B to be received by the advance restricting device 5. I am trying to let you. By doing so, even if the fuel injection timing control target value does not reach the maximum advance position A or the minimum advance position B, the stepping motor 3
The movement deviation of the stepping motor 3 can be corrected by restricting the movement.

Further, stepping is performed by setting the above-mentioned control position deviation calibrating rotation ranges C ₁ and C ₂ on the high speed side or the low speed side of the engine near idle speed and rated speed where the engine is always operated once. The operation deviation of the motor 3 can be corrected in the normal operating condition of the engine. Therefore, according to the present invention, even if the operation deviation of the stepping motor 3 occurs during engine operation, it is highly likely that the operation deviation of the stepping motor 3 can be corrected at appropriate times in the normal operating state, and appropriate advance control is performed. It can be carried out.

To explain further, the present inventors utilize the operation deviation correction action of the stepping motor 3 by providing the advance angle restrictor 5, and at the same time, control position deviation calibration rotation ranges C ₁ and C _{2 are used.}
By setting the
By the calibration operation by, the operation deviation correction action of the stepping motor 3 is exerted in the engine operating range where the maximum advance position A or the minimum advance position B is not reached, and the control position curve of the rotation range C ₁ , C ₂ Since the average rate of change is very small, the injection timing control calculating means 6 is operated from the maximum advance position A to the minimum advance angle in the injection timing control rotation region D outside the control position deviation calibration rotation regions C ₁ and C _2. Even if the fuel injection timing control target value is calculated as an appropriate advance angle control value corresponding to the value of the rotational speed signal detection in the range corresponding to the position B, the accuracy of the advance angle position is not hindered and the advance angle operation deviation is prevented. The inventors have found that it is possible to eliminate the inconvenience that the advance angle accuracy is reduced by performing the correction operation, and have completed the present invention.

<Effects of the Invention> As described above, the present invention has the following unique effects.

(I) The operation deviation can be corrected.

Not the initial deviation, but the operation deviation of the stepping motor caused by some disturbance element during the engine operation can be automatically corrected during the engine operation, and the accumulation of the operation deviation during the engine operation can be prevented.

(II) It is possible to correct the operation deviation even if it does not reach the idle speed and rated speed. The low speed side control position deviation calibration rotation range C ₁ is set near the idle speed, and the high speed side control position near the rated speed. Set the displacement calibration rotation range C _2, and set those rotation ranges C ₁ , C
By performing excessive advance or retard control in ₂ , even if the stepping motor operation deviation occurs in the sequence type injection timing control device that is not the feedback type, the engine speed is close to the low idle speed or near the rated speed. If the predetermined control position deviation calibration rotation range is reached, the operation deviation can be automatically corrected.

(III) It can be carried out only by changing the control signal of the injection timing calculation device composed of a microcomputer, etc. by software, and no additional components such as sensors are required separately, so existing devices can be used easily and at low cost. Can be implemented.

(IV) Since it is possible to quickly correct the operation deviation by operating the engine at either the idle speed or the rated speed, it is possible to increase the possibility of correcting the operation deviation.

Generally, in most cases, a diesel engine is warmed up at an idle speed when the engine is started, and then operated at an increased speed up to a rated speed.
That is, the engine has a property that at least one of the idle speed and the rated speed is operated on one side for a predetermined time. The present invention, in consideration of the above properties, has a control position deviation calibration rotation range C ₁ and C ₂ that corrects the operation deviation on both the low speed side and the high speed side of the engine, so the engine is operating. If so, it is extremely likely that the operation deviation can be corrected.

(V) When correcting the operation deviation in the advance angle control of the fuel injection timing control, it is possible to eliminate the disadvantage that the advance angle accuracy decreases.

Near idle speed and sets the low-speed side control position shift calibration speed range C _1, and set the high-speed side control position shift calibration speed range C ₂ in the vicinity of the rated speed, these speed region C _1, Since the average rate of change of the control position curve at C ₂ is very small, the injection timing control computing unit has the maximum advance in the injection timing control rotation region D outside the control position deviation calibration rotation regions C ₁ and C _2. Even if the fuel injection timing control target value within the range corresponding to the minimum advance position B from the angular position A to the proper advance control value corresponding to the value of the rotation speed signal detection is calculated, the accuracy of the advance position is not impaired. Instead, by performing the operation of correcting the advance angle operation deviation, it is possible to eliminate the disadvantage that the advance angle accuracy is lowered.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic system diagram of a fuel injection timing control device of a diesel engine, FIG. 2 is a flowchart of the control device,
FIG. 3a is a relationship diagram of the engine speed-advance control signal value of the injection timing calculation device, FIG. 3b is a relationship diagram of the engine speed-advance control current value of the stepping motor, and FIG. 3c is an engine rotation. FIG. 4 is a relational view of the number-advance angle control position of the fuel injection timing adjuster, and FIG. 4 is a vertical sectional front view of the fuel injection pump.

In the fuel injection timing control system for the diesel engine of the present embodiment, the fuel injection pump 10 is fixed to the pump housing chamber formed on the front side of the cylinder block of the diesel engine E, and as shown in FIG. Is interlocked with the fuel injection cam shaft 12.

A rotary injection timing adjuster 4 is engaged above the plunger 13 of the fuel injection pump 10, and the injection timing adjuster 4 is engaged with a stepping motor 3 for control as shown in FIG. The plunger 13 is slid up and down to advance the fuel injection pump 10 by moving the fuel injection pump 10.
The angle is adjustable.

However, the engagement lever 20 is driven and advanced by an advance angle restricting device 5 (stopper) including a high speed side advanced angle restricting device 5a and a low speed side advanced angle restricting device 5b protruding from the side wall of the fuel injection pump 10. The upper and lower limits of are limited.

In addition, a flywheel 14 interlocked with the crankshaft of the engine E is provided with a ring gear 8 described below, and the ring gear 8 is provided with a rotation speed sensor 1 and a cylinder head.
The fuel injection nozzle 16 attached to the fuel injection pump 10
Connect to. Then, the rotation speed sensor 1 and the stepping motor 3 are interlocked with the injection timing calculation device 2, respectively, and the injection timing calculation device 2 makes the fuel injection timing control target based on the rotation speed detection signal of the rotation speed sensor 1. The value is calculated, the stepping motor 3 is controlled and driven, and the fuel injection timing adjuster 4 is advanced and controlled in accordance with the value of the rotation speed detection signal.

The fuel injection timing calculation device 2 is composed of a microcomputer, and the value of the rotation speed detection signal of the rotation speed sensor 1 is within the control position deviation calibration rotation range C ₁ , C ₂ (see FIG. 3a). It is configured to include a function for detecting the state, an injection timing control calculation unit 6, and a control position deviation calibration calculation unit 7.

The injection timing control calculation unit 6 determines that the value of the rotation speed detection signal of the rotation speed sensor 1 indicates the injection timing control rotation range D (see FIG. 3A).
In the injection timing control state that falls within the range of (1), the target value for fuel injection timing control is calculated to a proper advance control value corresponding to the value of the rotation speed detection signal, and the stepping motor 3 is appropriately controlled and driven to perform fuel injection. The timing adjuster 4 is configured to perform an advance control operation corresponding to the value of the rotation speed detection signal.

As shown in FIG. 3a, the control position deviation calibration calculation unit 7 sets the fuel injection timing control target value to an excessive advance angle higher than the maximum advance value a in the control position deviation calibration rotation range C ₂ on the high speed side. The value h is calculated, and the target value for fuel injection timing control is calculated to be an excessive retardation value 1 lower than the minimum advance value b in the control position deviation calibration rotation range C ₁ on the low speed side. When the fuel injection timing adjuster 4 is excessively controlled and driven, the fuel injection timing adjuster 4 is calibrated to each of the maximum advance position A and the minimum advance position B to advance the advance limit device 5.
Let them take it.

Next, an example of setting the control position deviation calibration rotation ranges C ₁ and C ₂ will be described.

For example, when the maximum rotation speed is R ₂ rpm and the low idle rotation speed is R ₁ rpm, (1) the rotation range C ₂ for high speed side position deviation calibration is set to the maximum rotation side of the engine E under the following conditions. , R ₂ -100 rpm ≤ C ₂ ≤ R ₂ rpm (2) Low speed side misregistration calibration rotation range C ₁ is set to the low idle rotation side under the following conditions, and R ₁ rpm ≤ C ₁ ≤ R ₁ +100 rpm (3 ) The normal speed range excluding the low speed and high speed side calibration speed ranges, that is, the speed range higher than R ₁ +100 rpm and lower than R ₂ -100 rpm (which corresponds to the rated speed) is set as the injection timing control speed range. Set to D.

Next, the operation of the fuel injection timing control system for the diesel engine of this embodiment will be schematically described based on the flowchart shown in FIG.

When operating the diesel engine E, step SP1
In step SP2, the rotational speed sensor 1 detects the rotational speed of the diesel engine E, and in step SP2, the rotational speed is within the low speed side position deviation calibration rotational range C ₁ by the detection function of the fuel injection timing control device 2. If it is determined that the rotation speed is within the low-speed side displacement calibration rotation range C ₁ , the control position displacement calibration calculation unit 7 is operated in step SP3.
Outputs to the stepping motor 3 a control signal with an excessive retard value l. The stepping motor 3 which has received the output of the excessive retard angle value 1 excessively drives the adjuster 4 to the retard side, contacts the low speed side limiter 5b, and receives it at the minimum advance position B.

Further, in step SP2, the fuel injection timing control device 2
When it is determined that the rotation speed is not within the low-speed side displacement correction rotation range C ₁ , it is determined in step SP4 whether the rotation speed is within the high-speed side displacement correction rotation range C ₂ . If it is determined that the rotation speed is within the high-speed-side position deviation calibration rotation range C ₂ , the control position deviation calibration calculation unit 7 causes the stepping motor 3 to generate an excessive advance angle value h in step SP5.
Output a control signal. The stepping motor 3 which has received the output of the excessive advance angle value h excessively drives the adjusting tool 4 to the advanced angle side, contacts the high speed side restricting tool 5a, and receives it at the maximum advance angle position A. Therefore, when the stepping motor 3 is displaced due to some disturbance element during the operation of the engine E by the processing of the steps SP3 and SP5, the rotational speed of the engine E is displaced toward the low speed side or the high speed side. At the time of proceeding to the calibration rotation regions C ₁ and C ₂ , the deviation correction function of the advance angle limiting device 5 operates, and the position deviation (operation deviation) of the stepping motor 3 is promptly corrected.

On the other hand, in step SP4, the fuel injection timing control device 2 changes the rotational speed to the high speed side position deviation calibration rotational range C ₂
If it is determined that it is not within the range, the rotation speed is within the injection timing control rotation range D in FIG. 3a, and therefore, in step SP6, the injection timing control calculation unit 6 normally causes the stepping motor 3 to operate. The control signal of the target value for fuel injection timing control is output, and the adjusting tool 4 is controlled and driven to the advance position corresponding to the detection signal by the stepping motor 3 which receives the control signal.

The operation of this embodiment will be described in more detail with reference to FIGS. 3a to 3c.

In the control position deviation calibration state, the control position deviation calibration calculation unit 7 sets the target value for fuel injection timing control to an excessive advance value h higher than the maximum advance value a and an excessive retard value lower than the minimum advance value b. Since both the value 1 and the value 1 are calculated, the advance control curve F ₀ of the injection timing calculation device 2 is drawn as shown in FIG.

Therefore, the advance control current curve M ₀ of the stepping motor 3 to which the control signal from the injection timing calculation device 2 is input is as shown by the solid line in FIG. 3b.

Since the control position of the adjuster 4 is restricted by the advance limiter 5 in the region of the maximum advance value A to the minimum advance value B, the limit position on the low speed side of the control position deviation calibration rotation region C. Is equal to the minimum advance value B, the limit position on the high speed side is equal to the maximum advance value A, and the control position curve N ₀ of the adjuster 4 is as shown by the solid line in FIG. 3c.

In this case, in the control position deviation calibration rotation range C, the control position curve N ₀ deviates from an appropriate position curve n ₀ (see FIG. 7c) shown in a comparative example described later, but in this region C Since the average change rate of the control position curve is very small, the accuracy of the advance position is not hindered even if the position curve N ₀ is replaced with the proper curve n ₀ .

Therefore, because the stepping motor 3 causes an operation deviation due to some disturbance factor, the advance control current curve corresponding to the control curve F ₀ of the injection timing calculation device 2 deviates upward from the proper curve M ₀ and M ₁ (first 3b, the corresponding control position curve of the adjuster 4 is the curve N ₁ shown by the broken line in FIG. 3c.

That is, the control position of the adjuster 4 is reduced to the retard angle side to the minimum advance angle value B on the low speed side of the control position shift calibration rotation range C in proportion to the excessive retard angle value 1 of the injection timing calculation device 2. At the same time, on the high speed side of the control position deviation calibration rotation range C, the high speed side advance angle limiting device 5 is directly hit to reach the maximum advance angle position A. As a result, even if the engine E is operated on either the low speed side or the high speed side of the control position deviation calibration rotation range,
Since the advance position of the adjuster 4 reaches either the maximum advance value A or the minimum advance value B, and is thereafter controlled in the opposite direction, the adjuster 4 moves to the reference position curve N _0. The operation deviation is promptly corrected by the received control, and it becomes possible to control and drive the injection timing appropriately.

This also applies when the voltage curve of the stepping motor 3 deviates downward from the reference curve M ₀ to become M ₂ (one-dot chain line in FIG. 3b). On the high speed side of the control misregistration calibration rotation range C, the control position misalignment calibration rotation is performed while rising to the advance angle side in proportion to the excessive advance angle value h of the injection timing calculation device 2 and reaching the maximum advance angle value A. On the low speed side of the region C, the low speed side advance angle limiting device 5 is directly connected.
And reaches the minimum advance angle position B.

Therefore, the adjuster 4 moves on the descending position curve N ₂ (the one-dot chain line in FIG. 3c), and the advance position of the adjuster 4 is no matter whether the engine E is operated at the low speed side or the high speed side. Maximum advance value A
And the minimum advance value B are reached, it is possible to control and drive the injection timing appropriately.

It should be noted that the present invention is not limited to the embodiments described with reference to FIGS. 1 to 4 above, and various modifications and applications are possible within the scope of the present invention.

For example, in the above-described embodiment, the control deviation calibration calculation unit 7 calculates the excessive advance value h in the high speed side misregistration calibration rotation range C ₂ , and the excess advance value h in the low speed side misregistration calibration rotation range C ₁ . Although the retard value 1 is calculated, the fuel injection timing adjuster 4 is substantially operated in the control position deviation calibration rotation range C.
Should be calculated as a target value for calibrating up to either the maximum advance position A or the minimum advance position B, and is particularly limited to the method of setting the excessive advance value h and the excessive retard value l. Not something that is done.

<Comparative Example> Hereinafter, although the operation deviation correction function of the stepping motor 3 by the advance angle limiting tool 5 is provided, the control position deviation calibration calculation unit 7 does not perform the calibration operation without setting the control position deviation calibration rotation range C. A comparative example when there is no such case will be described.

The operation of this comparative example will be described below with reference to FIGS. 7 and 8. In this comparative example, the advance angle limiting device 5 (high speed side advance angle limiting device 5a, low speed side advance angle limiting device 5b, not shown in FIG. 8) is provided in FIG. Further, FIG. 7a is a third example showing a comparative example.
The equivalent view of FIG. A, FIG. 7b are equivalent views of FIG. 3b showing the same comparison example, and FIG. 7c is the equivalent view of FIG. 3c showing the same comparison example.

(1) First, the injection timing control calculation unit 41 changes the advance angle value to the minimum advance angle value b as shown in FIG. 7a from low idle rotation to maximum rotation, which is the rotation region during normal operation of the engine E. To a maximum advance value a consistently and smoothly (that is, the rate of change is positive at any rotation speed), the advance value corresponding to each rotation speed is set based on the control map f _0. This advance angle control signal is calculated and output to the stepping motor 3. (2) The stepping motor 3 matches the input advance angle control signal based on the advance angle control current curve m ₀ of FIG. 7b. To output the electric current to control and drive the fuel injection timing adjusting tool 4, and (3) the fuel injection timing adjusting tool 4 which has been actuated by the stepping motor 3 has the minimum advance position B from the low idle rotation to the maximum rotation. Between the maximum advance angle position A and the maximum advance angle position A Lead angle control position curve n ₀ set to make the control position variable
Based on (FIG. 7c), the advance position is changed to properly adjust the injection timing of the fuel injection pump.

However, in this comparative example, if an operation deviation occurs in the stepping motor 3 due to some disturbance factor during operation of the diesel engine E, the stepping motor 3
As a result, the advance control current curve of ₁ shifts from the appropriate curve m _0, and the advance control position curve of the adjuster 4 also deviates from the appropriate curve n _0, and the appropriate injection timing based on the signal of the injection timing control calculation unit 6 There is a problem that adjustment becomes impossible.

That is, the current curve of the stepping motor 3 is an appropriate curve m ₀
If the position curve of the adjuster 4 shifts upward from the proper curve n ₀ in response to an upward deviation from m to m ₁ , the adjuster 4 moves the upper and lower parts of the adjustment region by the advance angle restrictor 5. The position curve of the adjuster 4 is limited because it can move only between the maximum advance position A and the minimum advance position B, and the control position is limited to the region of both positions A to B. As shown by the broken line of c
n ₁ .

Therefore, even if an appropriate control signal is output from the injection timing control calculation unit 6, the adjustment position of the adjustment tool 4 is displaced upward from the appropriate position.

Therefore, if the rotation speed of the engine E decreases after reaching the maximum rotation speed, the position curve of the adjuster 4 is a proper curve n ₀ due to the decrease in the current value of the stepping motor 3 due to the decrease in the advance angle control signal. However, if the engine E continues to operate near the low idle speed, the adjuster 4 will continue to make adjustments on the ascending curve n ₁ . The injection timing of the fuel injection pump remains uncorrected and shifted.

This can also be said when the current curve of the stepping motor 3 deviates downward from the proper curve m ₀ to m ₂ , and the adjuster 4 moves the downward position curve n ₂ (one point in FIG. 7c). If the vehicle moves on the chain line) and continues to operate the engine E near the maximum rotation speed, the injection timing is still deviated.

Moreover, since the present fuel injection timing control device is a sequence type, that is, an open loop type and not a feedback type, it does not have a function of correcting the deviation of the stepping motor 3 by comparing it with an appropriate curve, and the adjusting tool 4 is not provided. In many cases, accurate injection timing control cannot be performed while leaving a misalignment.

As described above, the configuration of the comparative example is inferior in the advance angle control accuracy to the example.

<Reference example> Finally, instead of the open loop format as in the present invention,
An apparatus for correcting the operation deviation of the stepping motor 3 in the feedback type will be described for reference.

5 and 6 show a calibration device capable of correcting the positional deviation of the stepping motor 3 even when the engine E is operating, by detecting the advance position of the fuel injection timing adjusting tool 4 by the photo sensor.

That is, the engaging lever 20 of the adjuster 4 is provided with a circular detection rotary plate.
22 is attached, a large number of slits 23 are formed in the radial direction of the rotating plate 22, a photosensor 25 is arranged in a region through which the slits 23 pass, and the photosensor 25 is linked to the injection timing calculation device 2. If the actual advance position of the adjusting tool 4 is displaced from the proper advance position corresponding to the control signal from the arithmetic unit 2 due to the displacement of the stepping motor 3, the photo sensor
25 detects the actual advance angle position and uses this information as the calculation device 2
By feeding back to the stepping motor 3, a correction advance signal is output from the arithmetic unit 2 to the stepping motor 3.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, respectively.
FIG. 1 is a schematic system diagram of a fuel injection timing control device for a diesel engine, FIG. 2 is a flowchart of the fuel injection timing control device, and FIG. 3a is a relationship diagram of engine speed-advance control signal value of an injection timing calculation device. 3b, engine speed-advance control current value of stepping motor, FIG. 3c
Is a relationship diagram of the engine speed-advance angle control position of the fuel injection timing adjuster, FIG. 4 is a schematic vertical sectional view of the fuel injection pump, and FIG. 5 is a side view of a main portion of the fuel injection pump showing the fuel injection timing calibration device. Fig. 6 is a schematic system diagram showing the calibration device, Fig. 7
FIG. A is an equivalent view of FIG. 3a showing a comparative example, FIG. 7b is an equivalent view of FIG. 3b showing the comparative example, and FIG. 7c is an equivalent view of FIG. 3c showing the comparative example. FIG. 8 is a schematic system diagram of a conventional fuel injection timing control device for a diesel engine. 1 ... Rotation speed sensor, 2 ... Injection timing calculation device, 3 ...
... Stepping motor, 4 ... Fuel injection timing adjuster, 5
...... Advance limiter, 6 ...... Computation unit for controlling injection timing, 7 ......
Control position deviation calculation unit, A ... maximum advance position, B ...
… Minimum advance position, C ₁ …… Low speed side misalignment calibration rotation range,
C ₁ …… High speed side misregistration calibration rotation range, a …… maximum advance value, b …… minimum advance value, h …… excess advance value, l …… excess retard value, E …… diesel engine .

Claims (1)

(57) [Claims] 1. An injection timing calculation device (2) calculates a target value for fuel injection timing control based on a rotation speed detection signal of a rotation speed sensor (1) of a diesel engine (E), and stepping is performed by the target value. Control the motor (3),
In a sequence type fuel injection timing control device for a diesel engine, which is configured to advance and control a fuel injection timing adjuster (4) driven by a stepping motor (3) in accordance with the value of a rotation speed detection signal, The injection timing adjusting device (4) is provided with an advance angle restricting device (5) that receives the injection timing adjusting device (4) at each of the maximum advance position (A) and the minimum advance position (B). A control calculating means (6) and a control position deviation calibrating calculation means (7) are provided, and a low speed side control position deviation calibrating rotation range (C ₁ ) is set near the idle speed of the diesel engine (E). , The high-speed side control position deviation calibration rotation range (C ₂ ) is set near the rated speed, and the injection timing calculation device (2) sets the value of the rotation speed detection signal of the rotation speed sensor (1) to the control position deviation calibration. Rotation range (C ₁ ) In response to the detection of the state in the injection timing control rotation region (D) outside (C ₂ ), the injection timing control calculation means (6) changes from the maximum advance position (A) to the minimum advance angle (A). Position (B)
The target value for fuel injection timing control is calculated to a proper advance control value corresponding to the detected value of the rotation speed signal in the range corresponding to, and the stepping motor (3) is appropriately controlled and driven, and the fuel injection timing adjuster ( 4) is configured to perform an advance control operation corresponding to the value of the rotation speed detection signal, and the injection timing calculation device (2) adjusts the value of the rotation speed detection signal of the rotation speed sensor (1) to the control position deviation calibration. In response to detecting a state within the rotation range (C ₁ ) (C ₂ ) for
The control position deviation calibrating calculation means (7) sets the fuel injection timing control target value to an excessive advance value (h) higher than the maximum advance value (a) in the high speed side control position deviation calibrating rotation range (C ₂ ). The target value for fuel injection timing control is calculated to be an excessive retard value (l) lower than the minimum advance value (b) in the low speed side control position deviation calibration rotation range (C ₁ ), and the stepping motor is calculated. (3) is excessively controlled and driven, and the fuel injection timing adjusting tool (4) is calibrated to the maximum advance position (A) and the minimum advance position (B) respectively to advance the advance restricting device (5). ), A sequence type fuel injection timing control device for a diesel engine.