JPH08144827A - Fuel injection controller of diesel engine - Google Patents

Abstract

PURPOSE: To prevent change of an engine rotation by repeating the step difference of a fuel injection amount caused by the change over operation of a rotation angle pulse. CONSTITUTION: A rotation angle pulse signal is outputted at every prescribed engine rotation angle by a rotation angle sensor 29. In ECU 26, a fuel injection amount is calculated by the rotation angle and this rotation angle is divided by the rotation angle between rotation angle pulse signals and a rotation angle pulse number which is the quotient of an integer and a remaining angle are found out and this remaining angle is converted to a time. In ECU 26, when a remaining angle conversion time is smaller than a time required to set, the rotation angle pulse number is advanced by one and also the time interval of the prior rotation angle pulse signal and the remaining angle conversion time are added thereto. In this time, in ECU 26, when the fuel injection amount stays in an increased amount side, a larger value than the time required to set is made as a comparative value. In ECU 26, when the rotation angle pulse signal is matched with the rotation angle pulse number, the remaining angle conversion time is set as the opening timing of an electro-magnetic valve 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine fuel injection control device.

[0002]

2. Description of the Related Art As a fuel injection device for calculating a fuel injection amount by a rotation angle and controlling the result at the valve opening timing of a solenoid valve, there is a fuel injection device disclosed in JP-A-4-86352. This is because the rotation angle corresponding to the calculated injection amount is divided by the interval (rotation angle) of the reference rotation angle pulse signal to obtain the rotation angle pulse number and the remainder angle which are integer quotients, and this remainder angle is calculated. When the rotation angle pulse signal is converted into time and the rotation angle pulse number of the divided quotient coincides, the remainder angle conversion time is set and controlled as the valve opening timing of the solenoid valve.
At this time, for the time conversion of the surplus angle, the one before one cylinder (for example, 180 ° CA in the case of four cylinders) of the time interval of the input of the reference rotation angle pulse signal that encloses the valve opening timing is used. Further, this extra angle conversion time is too small, and the time To (for example, 88 μ) required for the processing from capturing the rotation angle pulse signal to setting the valve opening time is
It is known that, in the case of s) or less, the number of rotation angle pulses to be set is one before and the time obtained by adding the time interval of the rotation angle pulse signal of the previous cylinder at this rotation angle pulse number is set.

[0003]

However, in the above prior art, the surplus angle conversion time is calculated from the time interval of the rotation angle pulse of the previous cylinder, and as shown in FIG. , When decelerating), an error occurs. this is,
This is because the time interval of the rotation angle pulse signal that is the basis for time conversion of the surplus angle is long during acceleration and short during deceleration because it uses that of the previous cylinder, and this error is set after the rise of the rotation angle pulse signal. The time immediately before the angle corresponding to the required time To is the largest and the time immediately after it is the smallest. That is, a step occurs when the number of rotation angle pulses at the set time is switched.

The problem caused by this will be described with reference to FIG. In the fuel injection control of a diesel engine, there is a governor pattern as an injection characteristic that the injection amount is increased when the engine speed is decreased and is decreased when the engine speed is increased. As shown in FIG. 7, the opening position of the solenoid valve at the end of injection is T <88 μs (= To) as a result of the conversion of the surplus angle time T calculated by the number of rotation angle pulses 5 and 6 of the previous cylinder, and the opening is performed. As the valve time, the engine speed is kept constant while the time T45 is added to the time T45 of the rotation angle pulse numbers 4 and 5 of the previous cylinder from the rotation angle pulse number 4. At this time, if the load fluctuates due to some cause and the rotation drops, as shown in FIG. 7, the injection command value does not change, but the actual injection is the same as the previous valve opening time T45 + T.
Is set from the number of rotation angle pulses 4, which is less than the required amount. Therefore, the rotation tends to further decrease, but at this time, an increase command is issued from the decrease in rotation due to the governor pattern.

Then, while repeatedly increasing and decreasing the injection amount as shown in FIG. 7, it tries to converge to the initial state. However, since the surplus angle conversion time is near the switching of the rotation angle pulse number, the step of the actual injection amount due to the above-mentioned occurs at the time of switching. In FIG. 7, the surplus angle conversion time after the increase from the decrease in rotation is T> 88 μ from the rotation angle pulse time interval longer than the current time of the previous cylinder.
However, the actual injection increases more than the command value. Further, from the increase in rotation due to this increase, a command to decrease the amount is issued in FIG. At this time, time conversion of the surplus angle is performed from the rotation angle pulse time interval shorter than that of the previous cylinder, and since the surplus angle is large, the actual injection is further reduced than the command value. In this way, the states of FIG. 7 are repeated, and a surge phenomenon in which the rotation greatly changes occurs.

Therefore, an object of the present invention is to provide a fuel injection control device for a diesel engine which can prevent fluctuations in engine rotation due to repeated steps of the fuel injection amount caused by the switching operation of the rotation angle pulse number. It is in.

[0007]

According to a first aspect of the present invention, as shown in FIG. 8, a high-pressure fuel injected from a diesel engine is overflowed by a valve opening operation to adjust a fuel injection end timing, and a fuel is injected. Solenoid valve M1 for controlling injection amount
And a rotation angle sensor M2 that outputs a rotation angle pulse signal for each predetermined engine rotation angle, a fuel injection amount is calculated by the rotation angle, and this rotation angle is divided by the rotation angle between the rotation angle pulse signals to obtain an integer. The calculation means M3 for obtaining the quotient of the rotation angle pulse number and the remainder angle, and converting the remainder angle from the time interval of the previous rotation angle pulse signal in the rotation angle pulse number to the time, and the remainder angle conversion time. And the time required to set the valve opening time of the solenoid valve M1 after capturing the rotation angle pulse signal, and if the remainder angle conversion time is smaller than the set required time, the rotation angle pulse number And the rotation angle pulse number switching means M4 which sets the time obtained by adding the time interval of the previous rotation angle pulse signal in this rotation angle pulse number and the remainder angle conversion time as the remainder angle conversion time. A fuel injection control device for a diesel engine, comprising valve opening timing setting means M5 for setting the remainder angle conversion time as the valve opening timing of the electromagnetic valve M1 when the rotation angle pulse signal matches the rotation angle pulse number. When the fuel injection amount is on the increasing side, a comparison value in which the comparison value in the rotation angle pulse number switching means M4 is set to a value larger than the set required time instead of the set required time. Change means M
The gist is a fuel injection control device for a diesel engine equipped with No. 6.

According to a second aspect of the present invention, in the first aspect of the invention, the process by the comparison value changing means M6 is performed only when a predetermined condition in which rotation fluctuation may occur is satisfied. The gist is a fuel injection control device for a diesel engine equipped with a comparison value change limiting means M7.

[0009]

The calculating means M3 calculates the fuel injection amount by the rotation angle and divides this rotation angle by the rotation angle between the rotation angle pulse signals to obtain the rotation angle pulse number which is an integer quotient and the remainder angle. The remaining angle is converted from the time interval of the previous rotation angle pulse signal in the rotation angle pulse number to the time. The rotation angle pulse number switching means M4 compares the surplus angle conversion time with the time required to set the valve opening time of the solenoid valve M1 after capturing the rotation angle pulse signal to set the surplus angle conversion time. If it is smaller than the time, the number of rotation angle pulses is set to one, and the time obtained by adding the time interval of the previous rotation angle pulse signal at this number of rotation angle pulses and the remainder angle conversion time is set as the remainder angle conversion time. . The valve opening timing setting means M5 sets the remainder angle conversion time as the valve opening timing of the solenoid valve M1 when the rotation angle pulse signal matches the rotation angle pulse number.

When the fuel injection amount is on the increasing side, the comparison value changing means M6 replaces the set required time with a value larger than the set required time as the comparison value in the rotation angle pulse number switching means M4. That is, the comparison value in the rotation angle pulse number switching means M4 is provided with hysteresis, and when the fuel injection amount is on the increasing side, a value larger than the set required time becomes the comparison value, and the comparison result indicates the rotation angle pulse number. Switching is performed.

As a result, when the fuel injection amount is on the increasing side, by comparing the surplus angle conversion time with a value larger than the required set time, the switching operation of the rotation angle pulse number is suppressed, and the rotation angle pulse number is suppressed. It is possible to prevent the engine rotation from fluctuating due to the repetition of the step of the fuel injection amount due to the switching operation of.

According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, the comparison value change limiting means M7 is provided only when a predetermined condition in which the rotation fluctuation may occur is satisfied. The processing by the comparison value changing means M6 is performed. As a result, deterioration of fuel injection accuracy is avoided by changing the comparison value only when necessary.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a solenoid valve spill system based on a Bosch distribution type fuel injection pump according to an embodiment of the present invention. In this figure, a drive shaft 1 of the injection pump is drivingly connected to a crank shaft of a diesel engine (not shown), and the drive shaft 1 has a rotation speed of 1 of the crank shaft as the crank shaft of the diesel engine rotates.
/ 2 speed. Then, the vane feed pump 2 is driven by the rotation of the drive shaft 1. In FIG. 1, the vane type feed pump 2 is also shown in the form of being developed 90 degrees.

The vane type feed pump 2 introduces fuel from the suction port 3 to pressurize the fuel, regulates the fuel to a predetermined pressure through the fuel pressure regulating valve 4, and supplies the fuel to the fuel chamber 6 formed in the pump housing 5. . The drive shaft 1 drives the pressure-feeding plunger 8 via the coupling 7. The coupling 7 integrally rotates the pressure-feeding plunger 8 in the rotation direction, and allows the pressure-feeding plunger 8 to reciprocate in the axial direction. A face cam 9 is provided integrally with the pressure feed plunger 8. The face cam 9 is pushed by the spring 10 and the cam roller 11. The cam roller 11 and the face cam 9 have a known structure that converts the rotational movement of the drive shaft 1 into the reciprocating movement of the pressure-feeding plunger 8. The sliding contact between the cam roller 11 and the face cam 9 causes the cam crest of the face cam 9 to ride on the cam roller 11 to cause the pressure-feeding plunger 8 to move. Is reciprocated a number of times corresponding to the number of cylinders during one rotation.

The pressure feed plunger 8 is fitted to a head 12 fixed to the pump housing 5 to form a pump chamber 13. A suction groove 14 for each cylinder is formed in the pressure-feeding plunger 8. When one of the suction grooves 14 communicates with the suction port 15 during the suction stroke of the pressure-feeding plunger 8, fuel is introduced from the fuel chamber 6 into the pump chamber 13. To be done. During the compression stroke of the pressure-feeding plunger 8, the fuel in the pump chamber 13 is pressurized, and the fuel is sent from the distribution port 16 through the pressure-feeding valve 17 to the fuel injection valve of each cylinder in the diesel engine and injected into the combustion chamber of the diesel engine. .

A fuel metering mechanism 20 is connected to the pump chamber 13. In the fuel metering mechanism 20, when the supply of current to the coil 22 of the solenoid valve 21 is stopped, the needle valve 23 is lifted and the solenoid valve 21 is opened, so that the high pressure fuel in the pump chamber 13 overflows the passage 24. , 25 to be recirculated (overflowed) to the fuel chamber 6. Therefore, if the operation of the solenoid valve 21 is stopped during the compression stroke of the pressure-feeding plunger 8, the fuel injection is terminated. In other words, the high-pressure fuel injected from the diesel engine is caused to overflow by the opening operation of the electromagnetic valve 21, so that the fuel injection end timing is adjusted and the fuel injection amount can be controlled. Here, the solenoid valve 21
The timing for ending the energization of the fuel (the timing for ending the fuel injection) is an electronic control unit (hereinafter referred to as ECU) 2 such as a microcomputer.
It is supposed to be done by 6. The ECU 26 receives signals from the engine operating state detected by various sensors of the diesel engine, such as the temperature sensor 27 and the accelerator pedal sensor 28, and a signal from the rotation angle sensor 29, and energizes the solenoid valve 21 by a logical operation function described later. To control.

FIG. 2 is a rotation angle sensor 2 taken along the line AA of FIG.
It is a figure which shows 9. The rotation angle sensor 29 includes a disk 31 having a plurality of protrusions 30 integrally attached to the drive shaft 1 of the injection pump, and a proximity detector 32 such as a known electromagnetic pickup that detects passage of the protrusions 30. . In a 4-cylinder diesel engine, the protrusion 30 of the disk 31 is 9
0 ° / 16 = 5.625 ° lined up at intervals of 90 on disk 31
There are two protrusions 33 for each projection. Then, the drive shaft 1 of the injection pump rotates 90 °, that is, the engine 180
A missing angle 33 is detected for each crank angle and used as a reference angle, and a rotation angle pulse signal for detecting the protrusion 30 for each 11.25 ° crank angle of the engine is output. In this sensor output signal, the protrusion 30 is projected against the reference angle accompanying the passage of the missing portion 33.
0, 1 at each rising edge of the pulse accompanying the passage of
The number k of rotation angle pulses is determined as No. 2, No. 2, ...

In this embodiment, the ECU 26
The calculation means, the rotation pulse number switching means, the valve opening timing setting means, the comparison value changing means, and the comparison value changing limiting means are configured.

Next, the operation of the fuel injection control device for the diesel engine thus constructed will be described. Figure 3 shows EC
It is a timing diagram which shows the basic concept of injection amount adjustment by U26. FIG. 3 (a) shows the pressure feed plunger 8 of the injection pump.
Of FIG. 3, (b) of FIG. 3 is an energization pulse signal to the spill metering solenoid valve 21, and (c) of FIG. 3 is a signal from the rotation angle sensor 29. The ECU 26 determines the fuel quantity q to be injected based on the load information from the temperature sensor 27, the accelerator pedal sensor 28, a pressure sensor (not shown), etc., and the injection quantity q
After the spill angle θ corresponding to the above, that is, the reference angle θ ° crank angle has elapsed, the energization of the spill solenoid valve 21 is stopped and the injection is terminated. The solenoid valve 21 must of course be closed again by the pressure-feeding plunger 8 during the intake stroke in preparation for the next injection. Compared with, the timing accuracy requirement does not have to be extremely small.

On the other hand, the spill angle θ ° CA, which is the valve opening timing of the spill solenoid valve 21, is an important parameter directly related to the injection amount, and needs to be controlled extremely accurately. The accuracy of the spill angle θ ° CA can be easily ensured if an infinitely small rotation angle pulse signal can be input, but at the current technical level etc., a finite number of rotation angle pulse signals and a time counter built in the control microcomputer. There is no choice but to do it together. In this embodiment, since the output interval angle θo of the rotation angle pulse signal is 11.25 ° CA, a small angle can be obtained by interpolation. First, the spill angle θ determined based on the required injection amount q is set to θ
Divide by o to obtain the quotient k (an integer) and the remainder angle θh. Therefore, the portion corresponding to θo × k ° CA can be correctly determined by the angle signal, but the remaining angle θh smaller than the minimum resolution θo of the angle signal can no longer be treated as an angle, so the previous cylinder at the rotation angle pulse number k The time interval of the rotation angle pulse signal is converted into a time corresponding to the remaining angle θh. From the above, the rotation angle pulse signal is k from the reference angle.
After the number of times has passed (that is, when the rotation angle pulse signal matches the number of rotation angle pulses), the surplus angle conversion time is set as the opening timing of the solenoid valve 21, and when the surplus angle θh has passed, the spill solenoid valve. 21 is opened.

As described above, the solenoid valve 21 is opened according to the rotation angle pulse number k and the remainder angle conversion time. In this embodiment, control is performed in consideration of the case where the remainder angle conversion time is very small. There is. Details of this control will be described below with reference to FIG.

First, when the remainder angle conversion time is smaller than the time (set required time) To required for setting the valve opening time of the solenoid valve 21 after the rotation angle pulse signal is captured, the number of rotation angle pulses is incremented by one. At the same time, the time obtained by adding the time interval of the rotation angle pulse signal of the previous cylinder in this rotation angle pulse number and the remainder angle conversion time is updated as the remainder angle conversion time. However, when such processing is performed, fluctuations in the engine rotation due to repeated steps of the fuel injection amount due to the switching operation of the rotation angle pulse number as described with reference to FIGS. That is, the fluctuation (surge phenomenon) of the engine rotation is as follows, as a result of time conversion of the surplus angle, whether the surplus angle conversion time T is the time To required to capture the rotation angle pulse signal and set the valve opening time or less. It is generated by repeating the step of the actual injection amount by switching the number of rotation angle pulses.

Therefore, this switching judgment value (judgment time)
Hysteresis is provided at To. That is, as a result of time conversion of the extra angle, when the time T is equal to or less than the set required time T _o1 shown in FIG. 4, the rotation angle pulse number is “−1”.
After that, when T> T _o2 (for example, 188 μs _when T _o1 = 88 μs plus 100 μs), the rotation angle pulse number is switched according to the increase or decrease. This hysteresis width (T _o2 -T _o1 ) is set to a value such that the number of rotation angle pulses is not frequently switched in the rotation fluctuation that causes surge development.

In the present embodiment, the required set time T _o1 is 88.
μs and comparison value T instead of the required set time
_o2 is 188 μs, and the hysteresis width (T _o2 −T _o1 ) is 100 μs.

Here, the switching determination value To has a higher precision as it is shorter as can be seen from FIG. On the other hand, always providing the hysteresis may lead to deterioration of accuracy in the normal control. Therefore, in this embodiment, it is determined whether or not a surge phenomenon may occur, and a hysteresis is provided if necessary.

This operation will be described with reference to the flow chart shown in FIG. FIG. 5 shows a process of calculating the rotation angle pulse number and the remainder angle conversion time. First, in step 101, the ECU 26 calculates the injection amount by the rotation angle according to various operating conditions which are not described. Then, the ECU 26 executes step 102.
The rotation angle between the rotation angle pulse signals that becomes the reference is θo
Then, the time set rotation angle pulse number that is an integer quotient is obtained, and the remainder angle θh is converted from the time interval at the same rotation angle pulse number of the previous cylinder to the remainder angle time T.

Next, the ECU 26 determines in step 103 whether or not the hysteresis request flag is set. This hysteresis request flag has a switching determination value T
This is for deciding whether to add hysteresis for o. Then, the ECU 26 proceeds to step 111 when the hysteresis request flag is not set and there is no hysteresis setting request. After performing the processing of steps 111 to 114 (processing of setting a hysteresis request flag which will be described later), the ECU 26 compares the extra angle conversion time T with the required set time T ₀₁ (88 μs) in step 107 to calculate the extra angle conversion time T. Is required time T ₀₁ (88
If it is smaller than μs), the number of rotation angle pulses is set to “−1” in step 108, and the remainder angle conversion time T is set to “−”.
The remainder angle conversion time T is updated by adding the time interval of the rotation angle pulse signal of the previous cylinder in the rotation angle pulse number subtracted by 1 ”.

If T ≧ T ₀₁ in step 107, the ECU 26 sets the rotation angle pulse number as it is without performing the process of step 108. In step 111, the ECU 26 compares the current rotation angle pulse number with the previous rotation angle pulse number to determine whether or not the rotation angle pulse number is in the decreasing direction. The hysteresis request flag is set in step 114 because it increases and there is a possibility of surge generation.

In steps 112 and 113, the ECU 26 determines that the remainder angle conversion time T is T ₀₁ (=) even if the previous rotation angle pulse number is the same as the rotation angle pulse number to be set this time.
If it is smaller than 88 μs), the rotation angle pulse number is subtracted by “−1” in step 108, and therefore, the hysteresis request flag is set as the amount decreasing direction in step 114.

On the other hand, the ECU 26 determines in step 103
If the Terrisys request flag is set, step 1
In 04, the number of rotation angle pulses to be set this time is
Judge whether it is larger than the number of rotation angle pulses set last time
However, if it is large, may surge occur?
From the complementary angle conversion time T to the comparison value T including the hysteresis
₀₂Move to step 121 for comparison with (188 μs)
To go.

If the current rotation angle pulse number is not larger than the previous rotation angle pulse number in step 104, the ECU 26 determines in step 105 that this state is the predetermined injection (for example, the same rotation angle pulse number until injection in the same cylinder). When it is 4 injections in 4 cylinders) or more, it is determined that the surge phenomenon has not occurred, and the hysteresis request flag is cleared in step 106. After that, the ECU 26 proceeds to step 107 to compare the remainder angle conversion time T with the required set time T ₀₁ (88 μs).

In step 121, the ECU 26 also compares the remainder angle conversion time T and a comparison value T ₀₂ (188) with hysteresis.
μs). Then, the ECU 26 executes step 1
If T ≧ T ₀₂ (188 μs) in step 21, step 12
It is assumed that the hysteresis width is exceeded in 2 and the hysteresis request flag is cleared, and the remainder angle conversion time T is set as it is with the rotation angle pulse number. The ECU 26 executes T in step 107.
<T ₀₁ (88 μs) or T <T in step 121
_{When 02} (188 μs), the rotation angle pulse number is decremented by “−1” in step 108, and the remainder angle conversion time T
Is added to the time interval of the rotation angle pulse signal of the previous cylinder in the rotation angle pulse number subtracted by "-1" to update the remainder angle conversion time T.

The processing timing shown in FIG. 5 must be performed after the final injection amount is calculated and before the injection time is set. The number of rotation angle pulses is set at an early cycle every time or sufficiently in time for the set time. (For example, 0) is performed in synchronization.

As described above, in determining the switching of the rotation angle pulse number in which the surge phenomenon occurs, the rotation angle pulse is provided by providing a hysteresis, which is not frequently switched near the switching, if necessary. Since the number does not change frequently and the step difference of the actual injection is not repeated due to the change, it is possible to eliminate the rotation fluctuation which is a surge phenomenon.

As described above, in this embodiment, the ECU 26 determines in step 104 of FIG. 6 whether or not the number of rotation pulses to be set this time is larger than the number of rotation pulses set last time, so that the fuel injection amount is increased. If it is on the increasing side, step 121
In place of the set required time T ₀₁ (= 88 μs), a value T ₀₂ (= 188 μ) larger than the set required time T ₀₁
s) as a comparison value and the remainder angle conversion time T is smaller than the comparison value T ₀₂ , the rotation angle pulse number is set to 1 before in step 108, and the previous rotation angle pulse signal at this rotation angle pulse number The time obtained by adding the time interval and the remainder angle conversion time is defined as the remainder angle conversion time T. Therefore, a hysteresis is provided in the comparison value, and when the fuel injection amount is on the increase side, the value T ₀₂ larger than the required set time T ₀₁ becomes the comparison value, and the rotation angle pulse number is switched according to the comparison result. As a result, when the fuel injection amount is on the increasing side, by comparing the surplus angle conversion time T with a value T ₀₂ larger than the set required time, the switching operation of the rotation angle pulse number is suppressed, and the rotation angle pulse number It is possible to prevent the engine rotation from fluctuating due to the repeated steps of the fuel injection amount caused by the switching operation.

Further, the ECU 26 executes step 10 in FIG.
Only when a predetermined condition in which rotation fluctuation may occur is satisfied by the processing of 3, 111 to 114, that is, the current rotation angle pulse number is smaller than the previous rotation angle pulse number, or Even if the number of rotation angle pulses matches the previous number of rotation angle pulses, hysteresis is provided when the remainder angle conversion time is less than the set required time T _01. Therefore, change the comparison value only when necessary. This makes it possible to avoid deterioration of accuracy.

As an application example of the present invention, in the above embodiment, fuel injection is performed by determining in step 104 of FIG. 5 whether the number of rotation pulses to be set this time is larger than the number of rotation pulses set last time. It was determined whether or not the amount is on the increase side, but from the rotation angle corresponding to the injection amount obtained in step 102 of FIG. 5, or the remainder angle conversion time including the rotation angle pulse number obtained from the rotation angle, It may be determined whether or not the injection amount is on the increase side. Furthermore, the fuel injection amount may also be calculated, and it may be directly determined from the injection amount whether or not the fuel injection amount is on the increase side.

Further, in the above-mentioned embodiment, the hysteresis is provided if necessary, but the hysteresis may be provided always when switching the number of rotation angle pulses. At this time, however, the value T ₀₂ to be compared with the surplus angle conversion time T includes not only the surplus angle conversion time T but also the number of rotation angle pulses to be set to determine whether the injection amount is the increase side or the decrease side. , T <
Either T ₀₁ (88 μs) or T ≧ T ₀₂ (188 μs) is used for switching. In other words, on the weight reduction side, T ₀₁ (88μ
If T <T ₀₁ (88 μs) compared with s), the previous rotation angle pulse number, and if T <T ₀₂ (188 μs) compared with T ₀₂ (188 μs) on the increasing side, the previous rotation angle pulse number The valve opening time is set by the number of pulses.

[0039]

As described above in detail, according to the first aspect of the present invention, it is possible to prevent the engine rotation from fluctuating due to the repeated steps of the fuel injection amount due to the switching operation of the rotation angle pulse number. Shows excellent effects.

According to the second aspect of the invention, the deterioration of accuracy can be avoided by changing the comparison value only when necessary.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a solenoid valve spill system according to an embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a timing chart showing the basic concept of injection amount adjustment.

FIG. 4 is a timing chart for explaining a rotation angle pulse and a valve opening signal.

FIG. 5 is a flowchart for explaining the operation.

FIG. 6 is a characteristic diagram for explaining the deviation of the injection amount.

FIG. 7 is an explanatory diagram for explaining a relationship between a rotation angle pulse and a valve opening signal.

FIG. 8 is a block diagram corresponding to a claim.

[Explanation of symbols]

21 ... Solenoid valve, 26 ... Calculation means, rotation pulse number switching means, valve opening timing setting means, comparison value changing means, ECU as comparison value changing limiting means, 29 ... Rotation angle sensor.

Claims (2)

[Claims] 1. A solenoid valve for controlling a fuel injection amount by adjusting a fuel injection end timing by overflowing high-pressure fuel injected from a diesel engine by a valve opening operation, and a rotation angle for each predetermined engine rotation angle. A rotation angle sensor that outputs a pulse signal, the fuel injection amount is calculated by the rotation angle, and this rotation angle is divided by the rotation angle between the rotation angle pulse signals. Calculating means for converting the remainder angle from the time interval of the previous rotation angle pulse signal in the rotation angle pulse number to the time, the remainder angle conversion time, and the electromagnetic angle after the rotation angle pulse signal is captured. The time required to set the valve opening time is compared, and if the remainder angle conversion time is smaller than the required setting time, the rotation angle pulse number is set to 1 before and the rotation angle pulse number is set. In the rotation angle pulse number switching means for setting the time interval of the previous rotation angle pulse signal and the remainder angle conversion time as the remainder angle conversion time, and the rotation angle pulse signal matches the rotation angle pulse number. At the time, the fuel injection control device for a diesel engine is provided with valve opening timing setting means for setting the surplus angle conversion time as valve opening timing of the solenoid valve, wherein the fuel injection amount is on the increasing side. In some cases, the fuel injection control device for a diesel engine is provided with a comparison value changing unit that uses a value larger than the set required time as a comparison value in the rotation angle pulse number switching unit instead of the set required time. . 2. The diesel engine according to claim 1, further comprising a comparison value change limiting unit that causes the comparison value changing unit to perform processing only when a predetermined condition in which rotation fluctuation may occur is satisfied. Fuel injection control device.