JPH0886239A - Fuel characteristic detection device and injection timing controller of diesel engine - Google Patents

Abstract

PURPOSE: To surely prevent misfire when a fuel temperature is increased at the time of using fuel of low viscosity. CONSTITUTION: A control sleeve position is adjusted in response to a driving quantity given to an actuator 52 for control sleeve drive, and the control sleeve position is detected by a sensor 54. A standard injection quantity Qt matching the standard fuel is calculated by a calculation means 55 according to the rotational speed and load of an engine, and an injection quantity is feedback- controlled by a corrective means 56 for matching idling rotational speed with target rotational speed at the time of idling. A real injection quantity QREAL is calculated from the detection value of the sensor 54 by a calculation means 58 during feedback-correction of the idling rotation, and then a variable amplitude ΔQ of the injection quantity is calculated by a calculation means 60 from the real injection quantity QREAL and an average value QAV, and then it is judged by a judging means 61 whether the standard fuel or the low viscosity fuel is used based on the variable amplitude ΔQ.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In a mechanical fuel injection pump of VE type or VM type, the pressure of a fuel chamber pumped by a feed pump changes according to the rotation speed of the feed pump, and the timer piston moves in response to the pressure of the fuel chamber. The configuration is such that the injection timing is changed.

Further, a timing control valve for adjusting the pressure in the high pressure chamber of the timer piston is provided on the basis of such a mechanical pump, the sensor for detecting the position of the timer piston detects the actual injection timing, and this is the target injection. There is also a technology that improves the accuracy of the injection timing by feedback-controlling the duty value given to the timing control valve so that it coincides with the timing (see the section on diesel injection in the "Automotive Technology Handbook" issued by the Society of Automotive Engineers of Japan). ).

[0004]

By the way, when the basic injection amount and the basic injection timing are matched with the reference fuel such as JIS No. 2 light oil, it is adjusted according to the usage environment in cold regions such as JIS No. 3 light oil. If low-viscosity fuel is used, the injection timing will be substantially delayed due to a decrease in pump efficiency of the feed pump inside the pump and an increase in the amount of leak in the plunger pressure-feeding stroke. When the temperature is increased, the fuel viscosity further decreases due to the increase in the outside temperature. Due to this further decrease in viscosity, misfires frequently occur during idling, resulting in poor drivability during idling.

In this case, during the feedback control of the idle rotation speed by using the low-viscosity fuel, there occurs a phenomenon that the injection amount increases while keeping the idle rotation speed constant. Utilizing this phenomenon, we first filed a technique for determining that the low-viscosity fuel is in use when the feedback amount of the injection amount exceeds a predetermined value (see Japanese Patent Application No. 5-235215). .

However, since this prior application device does not detect whether or not a misfire has occurred, it is not sufficient to reliably prevent the occurrence of a misfire when the fuel temperature rises when a low viscosity fuel is used.

Therefore, the present invention ensures the misfire when the fuel temperature rises when the low viscosity fuel is used, by determining whether or not the low viscosity fuel is used by catching the phenomenon peculiar to the misfire. The purpose is to prevent.

[0008]

As shown in FIG. 37, the first invention is a distribution type in which the control sleeve position is adjusted according to the drive amount given to the control sleeve drive actuator (for example, rotary solenoid) 52. Injection pump, a sensor 54 for detecting the position of the control sleeve, a means 55 for calculating a basic injection amount Qt matched with reference fuel according to the engine speed and load, and an idle speed target at idle. A means 56 for feedback-correcting the injection quantity so as to match the rotation speed, a means 57 for converting the feedback-corrected injection quantity Q into a drive quantity given to the control sleeve drive actuator 52, and a feedback correction for the idle rotation. Inside the control sleeve position sensor From the detected value of 54 and means 58 for calculating the actual injection quantity Q _REAL, average Q from the actual injection quantity Q _REAL
A means 59 for calculating the _AV, means for calculating a fluctuation amplitude ΔQ of the injection quantity from the average value Q _AV said the actual injection quantity Q _REAL 6
0 and means 61 for determining whether the reference fuel or the low-viscosity fuel is used based on the fluctuation amplitude ΔQ.

In a second aspect of the invention, as shown in FIG. 38, in the first aspect of the invention, the used fuel determination means 61 controls the variation of the injection amount for two fuels, the reference fuel and the low viscosity fuel. A memory 71 that stores a characteristic representing a frequency distribution of points consisting of the amplitude ΔQ and the injection amount fluctuation period T _AV.
And the actual injection amount Q when calculating the fluctuation amplitude ΔQ
Means 72 for calculating the fluctuation cycle T _AV based on _REAL
And means 73 for determining whether the point consisting of the calculated fluctuation period T _AV and the fluctuation amplitude ΔQ belongs to the region of the reference fuel or the region of the low viscosity fuel on the frequency distribution. .

In the third invention, as shown in FIG. 39 in the first invention, when the used fuel determination means 61 calculates the fluctuation amplitude ΔQ, the rotation fluctuation amount Δ of the engine.
A means 81 for calculating Ne, and a means 82 for calculating a ratio ΔQ / ΔNe of the fluctuation amplitude ΔQ and the rotation fluctuation amount ΔNe.
And a means 83 for determining whether the reference fuel or the low viscosity fuel is used by comparing the ratio ΔQ / ΔNe with a threshold value.

In the fourth aspect of the invention, as shown in FIG. 40, the fuel flow rate, which is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side, depends on the drive amount (eg, duty value) given to the timing control valve 53. A distributed injection pump to be adjusted, a sensor 91 for detecting the position of the timer piston, a means 92 for calculating a basic injection timing IT matched with reference fuel according to the engine speed, and a position of the timer piston. A means 93 for calculating the actual injection timing IT _REAL from the detected value of the sensor 91, and a feedback correction of the drive amount given to the timing control valve 53 so that the actual injection timing IT _REAL coincides with the basic injection timing IT during idling. Means 94 and during the feedback correction of the injection timing at idle From the detection value of the timer piston position sensor 91, the timing control valve 5
3, a means 96 for calculating the actual drive amount D _REAL to be given to No. 3, and a means 97 for calculating an average value D _AV from the actual drive amount D _REAL ,
A means 98 for calculating a fluctuation amplitude ΔD of the driving amount from the average value D _AV and the actual driving amount D _REAL, and whether the reference fuel is used or a low viscosity fuel is used based on the fluctuation amplitude ΔD. And a means 99 for determining whether or not it is provided.

In a fifth aspect of the present invention, as shown in FIG. 41, in the fourth aspect of the present invention, the used fuel determination means 99 controls the fluctuation of the driving amount for two fuels, the reference fuel and the low viscosity fuel. A memory 101 for storing a characteristic representing a frequency distribution of points consisting of the amplitude ΔD and the drive amount variation period T _AV.
And the actual drive amount D when calculating the fluctuation amplitude ΔD
Means 10 for calculating the fluctuation cycle T _AV based on _REAL
2, and means 103 for determining whether the point composed of the calculated fluctuation period T _AV and the fluctuation amplitude ΔD belongs to the region of the reference fuel or the region of the low-viscosity fuel on the frequency distribution. To do.

In a sixth aspect of the present invention, as shown in FIG. 42 in the fourth aspect of the present invention, when the used fuel determining means 99 calculates the variation amplitude ΔD, the engine rotation variation amount Δ.
A means 81 for calculating Ne, and a means 111 for calculating a ratio ΔD / ΔNe of the fluctuation amplitude ΔD and the rotation fluctuation amount ΔNe.
And a means 112 for determining whether the reference fuel or the low-viscosity fuel is used by comparing the ratio ΔD / ΔNe with a threshold value.

A seventh aspect of the invention is the fuel consumption determining means 6 according to any one of the first to sixth aspects of the invention.
1, 99 is provided with a means for issuing a warning when it is determined that the low viscosity fuel is in use.

In the eighth invention, as shown in FIG. 43, the control sleeve position is an actuator for driving the control sleeve (for example, a rotary solenoid) 5.
The fuel flow rate, which is adjusted according to the drive amount given to the valve 2, is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side.
A distribution type injection pump adjusted by a drive amount (for example, a duty value) given to the engine, means 92 for calculating a basic injection timing IT matched with reference fuel according to the engine speed, and the control sleeve position. A sensor 54 for detecting, a means 55 for calculating a basic injection amount Qt matched with the reference fuel according to the engine speed and load, and an injection amount so that the idle speed matches the target speed during idling. Feedback correction means 56 and the control sleeve driving actuator 52 for controlling the feedback injection quantity Q
57 for converting the actual injection amount Q _REAL from the detection value of the control sleeve position sensor 54 during feedback correction of the idle rotation, and an average value from the actual injection amount Q _REAL. A means 59 for calculating Q _AV , the average value Q _AV and the actual injection amount Q
Means 60 for calculating the fluctuation amplitude ΔQ of the injection amount from _REAL
And means 61 for determining whether the reference fuel or the low-viscosity fuel is used on the basis of the fluctuation amplitude ΔQ, and the basic injection timing IT when the low-viscosity fuel is used based on the determination result. Is used as the command injection timing IT _SET , and when the reference fuel is used, the basic injection timing IT is directly used as the command injection timing IT
Means 121 for calculating as _SET , and this command injection timing I
A means 122 for converting T _SET into a driving amount given to the timing control valve 53 is provided.

In the ninth aspect of the invention, as shown in FIG. 44, the fuel flow rate that is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side depends on the drive amount (eg, duty value) given to the timing control valve 53. A distributed injection pump to be adjusted, a sensor 91 for detecting the position of the timer piston, a means 92 for calculating a basic injection timing IT matched with reference fuel according to the engine speed, and a position of the timer piston. A means 93 for calculating the actual injection timing IT _REAL from the detection value of the sensor 91, and a feedback correction of the drive amount given to the timing control valve 53 so that the actual injection timing IT _REAL coincides with the command injection timing IT _SET during idling. Means 131 and during the feedback correction of the injection timing at idle A means 96 for calculating an actual driving amount D _REAL providing from the detected value of said timer piston position sensor 91 in the timing control valve 53, means 97 for calculating an average value D _AV from the actual driving amount D _REAL
And means 98 for calculating the drive amount variation amplitude ΔD from the average value D _AV and the actual drive amount D _REAL, and the variation amplitude Δ
Means 9 for determining whether the reference fuel or the low-viscosity fuel is used based on D
9 and, based on this determination result, the value obtained by advancing the basic injection timing IT when the low-viscosity fuel is used is the command injection timing I.
Means 121 for calculating the basic injection timing IT as it is as the command injection timing IT _SET is provided as T _SET and when the reference fuel is used.

The tenth aspect of the invention is, as shown in FIG.
The control sleeve position is the actuator for driving the control sleeve (eg rotary solenoid)
The fuel flow rate, which is adjusted according to the drive amount given to 52, is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side.
A distribution type injection pump that is adjusted by the drive amount (for example, a duty value) given to No. 3, a unit 92 that calculates a basic injection timing IT that matches the reference fuel according to the engine speed, and an advance of the injection timing. A memory 141 for storing the learning value ITg of the angle correction amount, and this memory 14
Means 14 for backing up the value of 1 even after the engine is stopped
2, a sensor 54 for detecting the position of the control sleeve, and a means 5 for calculating the basic injection amount Qt matched with the reference fuel according to the engine speed and the load.
5 and means 56 for feedback-correcting the injection amount so that the idle speed matches the target speed during idling.
A means 57 for converting the feedback-corrected injection amount Q into a drive amount given to the control sleeve drive actuator 52; and an actual injection amount based on the detection value of the control sleeve position sensor 54 during the feedback correction of the idle rotation. Means for calculating Q _REAL 5
8, the means 59 for calculating an average value Q _AV from the actual injection quantity Q _REAL, and means 60 for calculating a fluctuation amplitude ΔQ of the injection quantity from the average value Q _AV said the actual injection quantity Q _REAL, this variation Means 61 for determining whether the reference fuel or the low-viscosity fuel is used based on the amplitude ΔQ, and, based on the determination result, when the low-viscosity fuel is used, the basic injection timing IT is set to the learning value. A means 143 for calculating a value which is advanced with ITg as a command injection timing IT _SET , and when the reference fuel is used, the basic injection timing IT as it is as a command injection timing IT _SET , and this command injection timing IT _SET. Means 122 for converting to the drive amount given to the valve 53, and the fluctuation amplitude Δ
Means 144 for searching the advance angle correction amount ITc at the misfire timing based on Q, and means for determining the value obtained by adding the margin allowance ITp to the searched advance angle correction amount ITc at the misfire timing as the learning value ITg. 145 and.

The eleventh invention is, as shown in FIG.
A distribution type injection pump in which the flow rate of fuel that is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by the drive amount (eg, duty value) given to the timing control valve 53, and the position of the timer piston is detected. A sensor 91, a means 92 for calculating a basic injection timing IT matched with reference fuel according to the engine speed, a memory 141 for storing a learning value ITg of an injection timing advance correction amount, and this memory 141. Means 142 for backing up the value of the actual injection timing IT _REAL from the detected value of the timer piston position sensor 91, and the actual injection timing IT _REAL for the command injection timing IT when idling.
Means 1 for feedback-correcting the drive amount given to the timing control valve 53 so as to coincide with _SET
31 and means 95 for outputting the feedback-corrected drive amount to the timing control valve 53.
And means 96 for calculating the actual drive amount D _REAL to be given to the timing control valve 53 from the detection value of the timer piston position sensor 91 during the feedback correction of the injection timing at the time of idling, and the average from the actual drive amount D _REAL. a means 97 for calculating the value D _AV, and means 98 for calculating a fluctuation amplitude ΔD of the driving amount from the average value D _AV said the actual injection quantity Q _rEAL, the reference fuel based on the fluctuation amplitude ΔD is used Whether the low-viscosity fuel is used or not, and based on this determination result, when the low-viscosity fuel is used, a value obtained by advancing the basic injection timing IT with the learning value ITg is used as the command injection. Timing IT
_SET , and means 143 for calculating the basic injection timing IT as the command injection timing IT _SET as it is when using the reference fuel, and means 151 for searching the advance correction amount ITc at the misfire timing based on the fluctuation amplitude ΔD.
And the advanced angle correction amount IT at this searched misfire timing
A means 152 for determining a value obtained by adding the margin allowance ITp to c as the learning value ITg is provided.

In a twelfth aspect of the present invention, in any one of the eighth aspect to the eleventh aspect, the advance angle correction is canceled after a certain period of time has elapsed after the injection timing is corrected. And re-evaluate the fuel properties.

[0020]

In the first aspect of the present invention, the fuel property is judged based on the fluctuation amplitude ΔQ of the injection quantity, so it is judged not only when the low viscosity fuel is used but also when the misfire occurs due to the increase in the fuel temperature. can do.

Further, since no additional sensor is required, the cost does not increase.

In the second aspect of the invention, even if the fluctuation amplitude ΔQ of the injection quantity is the same value, the fluctuation cycle is further taken into consideration, so that the accuracy of judgment as to whether or not the low viscosity fuel is being used is further improved.

According to the third aspect of the present invention, the influence of the rotational fluctuation that normally occurs due to the fluctuation of the engine load or the like is eliminated from the judgment as to whether or not the low-viscosity fuel is being used, so the accuracy of the judgment of the fuel property is improved. .

In the fourth aspect of the invention, the fuel property is determined based on the drive amount variation amplitude ΔD. Therefore, not only when the low viscosity fuel is used, but also when the misfire occurs due to the increase in the fuel temperature. Can be done and does not require additional sensors.

Further, when the fuel property is judged based on the fluctuation amplitude of the driving amount, the control of the fuel injection amount remains mechanical because of the cost limitation, and the timing control valve controls electronically only the injection timing. It can also be applied to the injection pump.

According to the fifth aspect of the invention, even if the fluctuation amplitude ΔD of the driving amount is the same value, the fluctuation cycle is further taken into consideration, so that the accuracy of judgment as to whether or not the low viscosity fuel is being used is further improved.

In the sixth aspect of the present invention, the influence of the rotational fluctuation that is normally generated by the fluctuation of the engine load and the like is removed from the judgment as to whether or not the low-viscosity fuel is being used, so the accuracy of the judgment of the fuel property is improved. .

In the seventh invention, the driver recognizes from the warning that the fuel currently used is not suitable for driving. Therefore, a reference fuel having a viscosity higher than that of the current fuel is added, or the fuel is added. Replacing with the reference fuel prevents deterioration of drivability due to misfire during idling.

In the eighth aspect of the invention, when the low-viscosity fuel is used and the misfire occurs due to the increase in the fuel temperature, the injection timing is advanced and corrected, so that the misfire at the idle time is surely prevented. .

Also in the ninth aspect of the invention, when the low-viscosity fuel is used and the misfire occurs due to the rise in the fuel temperature, the injection timing is advanced and corrected, so that the misfire at the time of idling is reliably prevented. .

In the tenth aspect of the invention, the learning value ITg is determined during the previous operation using the low-viscosity fuel, and if the low-viscosity fuel is subsequently used during the current operation, the idle state after the start is started. The basic injection timing (I
The learning value ITg is added stepwise to T),
Even when starting the engine with a low-viscosity fuel, misfire is reliably prevented.

Also in the eleventh invention, when the learning value ITg is determined during the previous operation using the low-viscosity fuel and the low-viscosity fuel is continuously used during the current operation, the idle state after the start The basic injection timing (I
The learning value ITg is added stepwise to T),
Even when starting the engine with a low-viscosity fuel, misfire is reliably prevented.

According to the twelfth aspect of the invention, it is possible to deal with the change in the fuel property after the injection timing is corrected in advance.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an electronically controlled distributed fuel injection pump,
It is known.

First, fuel is sucked from a feed port 3 driven by a drive shaft (which is connected to the engine output shaft) 2 from an inlet (not shown) of the pump body, and the fuel introduced into the pump chamber 5 operates. At the same time that the part is lubricated, it is sent to the high-pressure plunger pump 7 through the suction port 6.

The plunger 8 of the pump 7 is fixed to a cam disc 9 connected to the drive shaft 2,
The drive shaft 2 is driven via the joint 2A in synchronization with the engine rotation. The cam disk 9 has the same number of fiber cams 10 as the number of cylinders of the engine, and each time the face cam 10 gets over the rollers 12 arranged on the roller ring 11 while rotating, it reciprocates by a predetermined cam lift.

When the plunger 8 reciprocates while rotating in this manner, the fuel sucked from the suction port 6 by this reciprocation is pumped from the distribution port 13 through the delivery valve 14 to the injection nozzle (not shown). It

On the other hand, the fuel injection amount is determined by the position of the control sleeve 16 which covers the cutoff port 15 formed in the plunger 8. For example, when the opening of the cutoff port 15 moves to the right side of the plunger 8 and crosses the right end of the control sleeve 16, the fuel that has been pressure-fed from the plunger high pressure chamber 7A to the distribution port 13 until then. , Cut-off port 1
Since it is released to the low pressure pump chamber 5 through 5, the pumping to the distribution port 13 is completed.

Therefore, when the control sleeve 16 is displaced relative to the plunger 8 in the right direction,
When the fuel injection end timing is delayed and the fuel injection amount increases, conversely, when the fuel injection end timing is delayed, the fuel injection end timing is advanced and the fuel injection amount decreases.

The control sleeve 16 is supported by a ball 23 eccentrically provided at the tip of a rotor (rotating shaft) 22 of a rotary solenoid (a kind of proportional solenoid) 21, and the control sleeve 16 is controlled according to the rotation angle of the rotor 22 shown in FIG. The position is displaced. As shown in FIG. 3, the rotational movement of the rotor 22 is converted into the linear movement of the control sleeve 16 in the left-right direction.

In FIG. 3, as the rotation angle of the rotor 22 in the clockwise direction increases, the control sleeve 16
Of the rotor 22 increases (the amount of fuel injection increases), the rotation angle of the rotor 22 in the clockwise direction is proportional to the duty value (ON time ratio per constant time) given to the rotary solenoid 21. I am trying to grow.

The fuel injection timing is adjusted by changing the relative position of the face cam 10 and the roller 12 by the roller ring 11.

The roller ring 11 is connected via a timer slide pin 25 to a timer piston 26 which is rotatable in the rotational tangential direction of the roller ring 11. As shown in FIG. 4, the fuel pressure in the pump chamber 5 is introduced into the high pressure chamber 28 on one end surface of the timer piston 26 that slides in the cylinder 27 through the passage 29, and the low pressure chamber 3 on the opposite side.
Although 0 is in communication with the suction side of the feed pump 3 and is in a state close to negative pressure, the elastic force of the spring 31 pushes back the timer piston 26.

When the fuel pressure in the pump chamber 5 rises as the engine speed increases, the timer piston 30 is pushed to the right in FIG. 4, thereby rotating the roller ring 11 in the direction opposite to the rotation of the cam disk 8. , It acts to relatively advance the injection timing. Face cam 10 of cam disk 9
When the vehicle rides on the roller 12, fuel is injected. Therefore, when the roller ring 11 is rotated in the direction opposite to the rotation direction of the cam disk 9, the roller 1 of the face cam 10 is rotated.
Therefore, the timing of riding on 2 becomes earlier, and the fuel injection timing with respect to the crank angle can be advanced.

However, the fuel pressure in the pump chamber 5 is
Since it increases linearly in proportion to the engine speed, the injection timing can basically only be advanced linearly in proportion to the engine speed. Therefore, if the fuel in the high pressure chamber 28 is leaked to the low pressure side by opening the timing control valve 33 provided in the bypass passage 32, the injection timing can be delayed even at the same rotation speed.
The leakage flow rate to the low pressure side is adjusted by the duty value (hereinafter referred to as TCV duty value) given to the timing control valve 33.

However, the TCV duty value is not the ON time ratio per fixed time, but the OV per fixed time.
FF time ratio. TCV duty value is 100%
(That is, the timing control valve 33 is at the fully closed position) and has the maximum advance angle, and at 0% (the timing control valve is at the fully open position), the minimum advance angle (the leakage flow rate to the low pressure side is maximum). OFF time ratio is 100%
This means that the timing control valve is in the non-energized state, and the reason why the timing control valve is in the fully closed position in the non-energized state is for fail-safe. For example, when the wiring to the timing control valve is broken, the timing control valve is in a fully closed state (that is, the same state as when the timing control valve is not provided).

FIG. 5 is a control system diagram of the above electronically controlled injection pump.

Control sleeve position sensor 38
Is attached integrally with the rotor 22 of the rotary solenoid 21 as shown in FIG. 2, and outputs a signal according to the rotation angle of the rotor 22. As shown in FIG. 4, the timer piston position sensor 39 converts the displacement amount of the timer piston 26 into a voltage value and outputs it.

The reference pulse is one pulse per revolution of the injection pump, and the scale pulse is 36 pulses per revolution of the injection pump. These pulses from the injection pump and the sensor signals of the control sleeve position sensor 38 and the timer piston position sensor 39 are
Sensor 36 for detecting the accelerator opening, water temperature sensor 4
0, the air conditioner switch 41, and a signal from the inhibitor switch 42 that detects the selector position of the automatic transmission are input to the control unit 35, and in the control unit 35 including a microcomputer,
The drive amounts given to the rotary solenoid 21 and the timing control valve 33 are both controlled. Based on the above two reference pulses and scale pulse from the injection pump, the control unit 35
It goes without saying that the pump rotation speed is calculated in the above, and the engine rotation speed (twice the pump rotation speed) Ne is further calculated from this pump rotation speed.

FIG. 6 is a flow chart for explaining the feedback control of the idle speed, which is a constant cycle (for example, 1
0 to 50 msec).

In FIG. 6, the engine speed Ne and the accelerator opening (opening of the accelerator pedal) CL are read in step 1, and the basic injection amount is read from these values in step 2 with reference to the map containing FIG. And calculate this as the variable Qt
Put in. This basic injection amount (Qt) is based on the reference fuel (JIS
No. 2 light oil).

At step 3, whether or not it is idle,
If it is idle, it is determined that the feedback condition is satisfied, and the process proceeds to steps 4-7.

First, in step 4, the target rotation speed Nt is set. The target rotation speed Nt is basically a rotation speed according to the cooling water temperature (the lower the temperature, the higher the target rotation speed).

In steps 5, 6 and 7, the actual rotation speed Ne
And the difference DN (= Ne-Nt) between the target rotation speed Nt and
From this difference DN, the feedback correction amount DQ is obtained by referring to the table having the contents of FIG. 8, and the value of this DQ and the value of Qt are added and put into the variable Q.

In step 8, the duty value (driving amount) Drot given to the rotary solenoid 21 is obtained from the value of Q by referring to the table having the contents of FIG. 9, and this is transferred to the output register in step 9. From this Drot value, ON and OFF pulses are generated and output to the rotary solenoid 21.

When the basic injection amount (Qt) and the basic injection timing (IT) described later are matched with JIS No. 2 light oil (reference fuel), JIS special No. 3 light oil or the like in cold regions. When low-viscosity fuel with specifications is used even in summer when the fuel temperature rises, the injection timing is substantially delayed due to a decrease in pump efficiency of the feed pump inside the pump and an increase in leak amount in the plunger pressure stroke. In addition, misfires frequently occur during idling, resulting in poor idling performance.

In order to cope with this, the control unit 35 uses the instantaneous fluctuation amplitude of the injection amount generated during the feedback control of the idle speed (or the instantaneous duty value of the timing control valve generated during the feedback control of the injection timing). (Variation amplitude) is calculated, and based on this fluctuation amplitude, it is determined whether low viscosity fuel is being used, and when low viscosity fuel is used, the basic injection timing matched to the reference fuel is used. Correct the lead angle.

FIG. 1 shows what happens to the injection quantity when the misfire is caused by raising the fuel temperature during the feedback control of the idle speed using JIS special No. 3 light oil.
0 (see the lower part), the figure is a simplified model of the experimental results. From the figure, not only the average value of the actual injection amount (Q _AV ) increases at the time of misfire compared to when JIS No. 2 diesel oil is used, but also a fluctuation that fluctuates up and down appears at regular intervals. The misfire occurring in one cylinder causes this one piece of the fluctuating mass.

As shown in the figure, the fluctuation of the injection amount first swings to the increasing side. The reason for swinging to the increasing side is, as shown in FIG. 11, the rotation speed drops due to misfire → injection for recovery. The amount is increased → However, the actual injection amount does not increase because the amount of leakage from the plunger, delivery valve, etc. is severe → The rotation speed continues to decrease and the amount increases further → The rotation increases finally → The injection amount increases It seems to be in the process of being reduced. In addition,
In FIG. 11 (also in FIG. 12 and subsequent figures, which will be described later), the low-viscosity fuel is represented by the light fuel.

On the other hand, when the actual injection timing is detected by the timer piston position sensor 39 and the TCV duty value is feedback-controlled so that this coincides with the target injection timing in order to improve the control accuracy of the injection timing during idling. Is as shown in FIG. 10 (see the upper part),
Corresponding to the fluctuation of the injection amount, the TCV duty value
The fluctuation appears periodically at almost the same timing.

However, the fluctuation of the TCV duty value first swings to the increase side, but does not swing to the decrease side unlike the injection amount. This is because in FIG. 4, the pressure in the high-pressure chamber 28 decreases due to an increase in the amount of leakage due to the decrease in fuel viscosity. → The timer piston 26 moves to the high-pressure chamber 28 side (retard side) → based on the timer piston. The TCV duty value is increased so as to squeeze the timing control valve 33 in order to return to the position. However, the TCV duty value is increased in order to follow the process in which the recovery of the pressure in the high pressure chamber 28 is delayed due to the large leak amount. This is because it is analyzed only when it swings to the increasing side (see FIG. 12).

The prior application device (Japanese Patent Application No. 5-235215)
No.) is J of the average value (Q _AV ) of the injection amount in FIG.
Based on the increase amount of IS2 gas oil and the average value of TCV duty values (D _AV ) from the use of JIS gas gas, it is determined whether special No. 3 gas oil is used or not. However, it is different from the device of the present application in that it does not pay attention to the fluctuation accompanying misfire.

FIG. 13 is a flowchart for explaining the judgment of the fuel property and the correction control of the injection timing using the judgment result, which is executed by a background job or at a constant cycle (for example, 10 msec).

In step 11, the engine speed Ne is read, and in step 12, the basic injection timing (see the solid line in FIG. 14) is obtained from this engine speed Ne by referring to the table having the contents shown in FIG. IT [mm]
Put in. This basic injection timing (IT) matches the reference fuel.

At step 13, it is checked whether the accelerator sensor 36 is in the idle state. When it is in the idle state, the advance angle correction flag is checked at step 14, and when it is not in the set state, the advance angle of the injection timing is corrected. If it is determined that it has not been performed, the process proceeds to step 15.

At step 15, the control sleeve position Ccs [V] is read, and at step 16, the actual injection amount at the time of idling is obtained from the value of this Ccs and the engine speed Ne by referring to the map having the contents of FIG. Put this in the variable Q _REAL [mg / st].

In step 17, the variation amplitude of the injection amount is calculated from the value of the variable Q _REAL and the average value of the injection amount stored in the memory (the variation amount of the injection amount per unit time from the average value). ΔQ is calculated by the following formula: ΔQ = (Q _REAL −Q _AV ) / ΔT (1) where Q _AV : moving average value of Q _REAL ΔT: unit time. The moving average value Q _AV of the injection amount will be described later with reference to FIG.

The battery voltage, the operation of the air conditioner,
In the case where the injection amount at the time of idling is increased and corrected according to the selector position in the vehicle with an automatic transmission, it is necessary to consider this increased correction amount. For example,
Step 7 in FIG. 6 for various increase corrections at idle
The injection amount Q in, Q = Qt + DQ (+ Q V + Qa + Qtr) ... (2) However, Q _V: increase correction amount Qa regarding battery voltage: increase correction amount Qtr equivalent to air conditioning load: increase correction amount corresponding to the torque converter load If you need to replace it with
The expression is changed to the expression ΔQ = {Q _REAL − (Q _V + Qa + Qtr) −Q _AV } / ΔT (3).

In step 18, the injection amount fluctuation amplitude ΔQ
Is compared with the threshold value Qth (> 0), and when ΔQ> Qth, it is determined that the low viscosity fuel is used, and step 1
Go to 9-21. The threshold value Qth is a value shown in the lower part of FIG. 10 (that is, an amplitude located slightly below the maximum peak value of fluctuation). When misfire occurs due to an increase in fuel temperature when low-viscosity fuel is used, the fluctuation of the injection amount on the increasing side is Q
It exceeds the value of th. An amplitude located slightly above the lowest peak value of the fluctuation of the injection amount is adopted as a threshold value (the threshold value in this case becomes a negative value), and the value of Q _REAL is smaller than this threshold value. It can sometimes be determined that the low viscosity fuel is being used. However, as shown in the lower part of FIG. 10, since the fluctuation range of the fluctuation of the injection amount toward the increasing side is larger than the fluctuation range of the fluctuation toward the decreasing side, the accuracy of the judgment becomes better when the fuel property is judged on the increasing side.

At step 19, a timer for measuring the advance angle correction time is started. This advance correction time is used in step 25 described later.

In step 20, the value obtained by adding the predetermined value ITt to the value of the variable IT is put into the variable IT _SET , and the advance angle correction flag is set in step 21. Since the value of the variable IT _SET representing the command injection timing is a value representing the crank angle before the compression top dead center, injection is performed by increasing the basic injection timing (IT) matching the reference fuel by the predetermined value ITt. The timing is advanced and corrected (see the broken line in FIG. 14). Even if the TCV duty value corresponding to the basic injection timing (IT) is given, when the low-viscosity fuel is used, the timer piston position moves to the retard side of the injection timing due to the decrease in the fuel viscosity. In order to restore it to the original, the injection timing is corrected to the advance side.

After the advance angle correction flag is set in step 21, the flow next proceeds from step 14 to step 25 to check if it is time to re-evaluate the fuel property. This is to compare the lead angle correction time measured by the lead angle correction timer with a specified time, and proceed to step 20 to continue the lead angle correction of the injection timing until the lead angle correction time reaches the specified time. To do.

When the lead angle correction time reaches the specified time,
Assuming that the fuel has been replaced or the operating atmosphere may have changed, the process proceeds to steps 15 to 18 to check whether the fuel property has changed. When the low-viscosity fuel is being changed to the reference fuel by refueling after starting the advance angle correction timer, the determination result in step 18 is ΔQ ≦ Qth because the misfire has stopped.
At this time, it is determined that the advance angle correction is not necessary, the advance angle correction timer is stopped in step 22, the timer recording contents are reset, the value of the variable IT is directly input to the variable IT _SET in step 23, and the step 24 is performed. Reset the advance angle correction flag with.

The determination as to whether or not it is time to re-evaluate the fuel property is not limited to this. For example, the pump rotation speed may be integrated, and when the integrated value becomes equal to or greater than the specified value, it may be determined that it is the reevaluation time. The specified value in this case is determined by using the integrated value of the pump rotation speed until the fuel tank is empty (specifically, the engine is operated several times and re-evaluated about once).

On the other hand, if the idle state is disengaged after the advance angle correction flag is set in step 21, step 2
If the advance angle correction flag is set and the advance angle correction flag is set, the process proceeds to step 20 and the advance of the injection timing is continued. In this case also, the advance correction of the injection timing is continued in order to cope with misfires occurring not only at the time of idling but also at the time of low load (for example, up to a running load of about 20 km / h). .

The above-mentioned moving average value Q _AV of the injection amount is executed in synchronization with the reference pulse from the injection pump as shown in FIG. 16, for example.

[0077] At the time of idling at step 31, the value of the variable Q _n in the variable _{Q n-1} in step 32, the variable Q
the value of _n-1 to the variable Q _n-2, the variable the value of the variable Q _n-2 Q _n-3
Move to. These four variables are for storing the latest past four actual injection amounts.

In steps 33 and 34, as in steps 15 and 16 of FIG. 13, the actual injection amount (Q
_REAL ), which is put in the variable Q _n in step 35.

At step 36, the moving average value Q _{AV of the} injection amount
Is calculated by the following equation: Q _AV = (Q _n + Q _n-1 + Q _n-2 + Q _n-3 ) / 4 (4), and this is stored in the memory in step 37. This stored value is read in step 17 of FIG.

FIG. 17 is a flow chart for performing feedback control of the injection timing, and the command injection timing (IT
_SET ) is executed after it is set. FIG.
The process of 7 is also executed by the background job or at a constant cycle (for example, 10 msec).

In step 41, the command injection timing (IT
_SET ) and the engine speed Ne to obtain the basic value of the TCV duty value with reference to the map having the content of FIG.
This is put in the variable DTY [%]. The value of DTY is shown in Fig. 1.
As shown in 8, the retard angle side is made smaller. This is TCV
The smaller the duty value is, the more the timing control valve is opened, the amount of leakage from the high pressure chamber 28 to the low pressure side is increased, and the timer piston position is moved to the retard side. Further, since the injection timing needs to be advanced as the rotation speed is lower, the engine speed N
The parameter e is also used.

At step 42, when it is idle at the time of idling, the timer piston position Ctp [V] is read at step 43, and the value of this Ctp is read at step 44 with reference to the table having the contents of FIG. Obtain the injection timing and put it in the variable IT _REAL [mm].

At step 45, the difference DIT between the actual injection timing and the command injection timing is obtained by the formula DIT = IT _REAL- IT _SET (5), and from this difference DIT at step 46 the table having the contents of FIG. 20 is referred to. Then, the feedback correction amount is obtained, and this is put in the variable DDTY [mm].

At step 47, the value obtained by adding the value of this DDTY to the value of the above-mentioned DTY is put into the variable DTY _SET representing the command TCV duty value, and at step 48 this is transferred to the output register. O from the value of this variable DTY _SET
N and OFF pulses are generated and output to the timing control valve 33.

On the other hand, when the engine is not idle, the value of the variable DTY is directly transferred to the variable DTY _SET in step 49.

The operation of this example will be described. When the accelerator sensor 36 detects a no-load state, the idle speed feedback control is started, and the actual engine speed Ne becomes equal to the target speed N _T. The injection amount is feedback-controlled so that they match.

At this time, the fluctuation amplitude ΔQ of the injection amount is calculated, and this is compared with the threshold value Qth. In this case, when the fuel temperature rises during the use of the low-viscosity fuel, the fluctuation amplitude ΔQ increases beyond the threshold value Qth due to misfire, so it is determined that the low-viscosity fuel is in use.
Basic injection timing (matched with reference fuel)
By advancing the injection timing by a predetermined value ITt from IT, an appropriate injection timing corresponding to low viscosity fuel can be obtained. The injection timing is not substantially retarded even when the fuel viscosity greatly decreases due to the increase in the fuel temperature when using the low-viscosity fuel.

Whether or not the low-viscosity fuel is being used is determined by the peculiar phenomenon that occurs at the time of misfire (that is, the instantaneous change in the injection amount). After determining that the misfire can be reliably prevented.

Further, even after the injection timing is corrected for the advance angle, the advance angle correction is canceled and the fuel property is re-evaluated after a lapse of a certain time, so that the injection timing is corrected for the advance angle. It is possible to cope with the change in fuel properties after it is decided to do so.

Furthermore, since no additional sensor is required, the cost does not increase.

FIG. 21 shows a second embodiment and corresponds to FIG. The same numbers are given to the same parts as in FIG.

Explaining only the portions different from those in FIG. 13, in step 18, the fluctuation amplitude ΔQ of the injection amount is set to the threshold value Q.
If it is larger than th, it is necessary to correct the advance angle of the injection timing. In this case, if the learned flag is checked in step 51 and this is set, the learned value ITg of the advance correction amount is already obtained. It is determined that the command injection timing (IT _SET ) is obtained by the equation: IT _SET = IT + ITg (6) where ITg is the learned value of the advance angle correction amount.

If the advance angle correction time has not reached the specified time in step 25 of FIG. 21, the learning angle timer value and the learning completion flag are checked in step 53 to determine the advance angle correction time (learning time timer) based on the learning value. (Measured with) has reached the specified time or the learned flag is in the reset state, the routine proceeds to step 54, where the learning value IT of the advance correction amount is obtained.
Determine g.

Now, how to determine the learning value ITg will be described with reference to the model shown in FIG. 23. In the figure, the timing for determining the learning value ITg (that is, the process proceeds from step 53 to step 54 in FIG. 21). The timing is when the injection timing is in the misfire area (hatched area). In this case, first, a predetermined value ITt is given as an initial advance correction amount to return to a region where misfire does not occur, and then the advance correction amount is gradually reduced (the injection timing is returned to the retard side) from this state. A value obtained by adding the margin allowance ITp to the advance angle correction amount at the timing when the misfire occurs is determined as the learning value ITg.

FIG. 22 (subroutine of step 54 in FIG. 21) is a flow chart for determining the learning value ITg, which is executed at a constant cycle (10 msec).

In step 61, it is determined whether or not it is the first time, and if it is the first time to proceed to step 61, the learning timing timer is reset in step 62, and the initial advance angle correction is made to the variable ITc representing the advance angle correction amount in step 63. Put the amount ITt,
In step 64, the value obtained by adding the value of the variable IT to the value of the variable ITc is transferred to the variable IT _SET .

From the second time, steps 61 to 6
Proceeding to step 5, the misfire limit is searched for in steps 65 to 69,64. That is, the fluctuation amplitude ΔQ of the injection amount is obtained in steps 65 to 67, and the fluctuation amplitude ΔQ and the threshold value Q are calculated in step 68.
Th is compared, and if ΔQ ≦ Qth, it is determined that there is still room before a misfire occurs, and the value of the variable ITc is set to ITc = ITc−ITr (7) where ITr: once The amount of retard angle per hit is gradually reduced to retard the injection timing.

By repeating the gradual decrease of the variable ITc, the injection timing gradually approaches the misfire region, and if the misfire eventually occurs, ΔQ> Qth, and at this time, step 6
The process proceeds from step 8 to steps 70 and 71, and a value obtained by adding the allowance ITp to the value of the variable ITc at the timing of misfire is determined as the learning value ITg of the advance correction amount.

Steps 72 and 73 are post-processing, in which the learning completion flag is set, the learning timing timer is started, the routine of FIG. 22 is terminated, and the process returns to the first step of FIG. The obtained learning value ITg is backed up even after the engine is stopped.

In the process of determining the learning value ITg, the injection timing feedback control shown in FIG. 17 is executed.

In this example, if the learning value ITg has been determined even once during the previous operation with the same fuel as the fuel currently used, the injection timing suitable for the fuel currently used is immediately after the restart of this time. Can be given. When the learning value ITg is determined during the previous operation using the low-viscosity fuel and the low-viscosity fuel is continuously used during the current operation, the basic injection timing ( The learned value ITg is added stepwise to (IT) (see FIG. 24), and even when starting the engine with low-viscosity fuel, misfire can be reliably prevented.

FIG. 25 shows a third embodiment, which is the same as FIG. 1 of the first embodiment.
Corresponds to 3.

In this example, since ΔQ> Qth, when a low-viscosity fuel is used and a misfire occurs due to an increase in the fuel temperature, a warning light provided on the operation panel is turned on (or a warning buzzer is turned on). (Step 18, 8)
1) The driver is notified.

From the lighting of the warning light, the driver recognizes that the special cold diesel fuel, which is a fuel for the extremely cold season, is not suitable for driving because the outside air temperature (fuel temperature) is high, and it is more viscous than JIS clean diesel oil. By adding high light oil or replacing the fuel with high-viscosity light oil, it is possible to prevent deterioration of drivability due to misfire during idling.

26 and 27 show the fourth embodiment, and FIG. 26 corresponds to FIG. 25 of the third embodiment.

In this example, the variation amplitude ΔQ of the injection amount is integrated for a predetermined time and the value is stored (steps 102, 103, 104, 105, 106, 10 in FIG. 27).
7), the stored integrated value ΔQsum and threshold value Q
By comparing thS, when ΔQsum> QthS, it is determined that the low-viscosity fuel is being used, and the warning light is turned on (steps 91 and 81 in FIG. 26).

Even when misfire occurs due to an increase in the fuel temperature when using a low-viscosity fuel, the fluctuation amplitude ΔQ of the injection amount may not be caught by the threshold value Qth as shown in FIG. 28. Since it is not judged that the viscous fuel is being used, the deterioration of drivability due to misfire does not stop. On the other hand, by using the integrated value ΔQsum of the fluctuation vibration of the injection amount in this example, it can be determined that the low-viscosity fuel is being used even in the case shown in FIG.

Instead of the integrated value ΔQsum, the integrated value of the actual injection amount itself per unit time can be used.

29 and 30 show a fifth embodiment, and FIG. 29 corresponds to FIG. 25 of the third embodiment.

In this example, assuming a multi-cylinder engine,
Not only the fluctuation amplitude ΔQ of the injection amount, but also the fluctuation period of the injection amount (see the lower part of FIG. 10) is added to determine the fuel property. As shown in FIG. 29, the fluctuation amplitude ΔQ of the injection amount
From the fluctuation cycle and the fluctuation cycle, referring to the map having the content of FIG. 31, it is determined that the low-viscosity fuel is used if the point consisting of the fluctuation amplitude ΔQ and the fluctuation cycle in FIG. 31 is in the right region (FIG. 29). Steps 111, 81).

FIG. 31 shows the frequency distribution of the fluctuation amount and fluctuation period of the injection amount, and the position of the boundary line (called the standard frequency curve) that divides the two regions reflects the experimental results. is there. The boundary line may be simply approximated by a straight line.

The reason why the variation cycle of the injection amount changes in the multi-cylinder engine is as follows. The misfire occurs from the cylinder where the fuel leaks the most. For example, if it occurs in the first cylinder, the fluctuation cycle is four cylinders (the injection order is # 1- # 3- #).
4- # 2), the crank angle is 180 × 4
(= 720) ° (see the upper part of FIG. 32). Next, if the fuel temperature further rises and misfire occurs in the third cylinder, the fluctuation cycle is 180 × 2 (= 360) in crank angle.
And the fluctuation cycle is halved (see the lower part of FIG. 31).
If a misfire occurs in all cylinders, the crank angle will be 180
° is the fluctuation period. As described above, in the multi-cylinder engine, the fluctuation cycle changes depending on the degree of misfire.

As the fluctuation cycle, as shown in FIG. 30, the moving average value T _AV of the fluctuation cycle can be used.
In FIG. 30, in steps 121 and 122, the maximum value of the actual injection amount is sampled into a variable Q _PEAK , and if it exceeds the reference value in step 123, it is determined that it is the timing at which the fluctuation has occurred due to misfire, and the fluctuation cycle Moving average (T
_AV ) (steps 124, 125, 12 in FIG. 30)
6, 127), and this is coupled with ΔQ obtained at the same timing and stored (steps 104, 128 in FIG. 30).

In this example, even if the value of ΔQ is the same, since the fluctuation period (T _AV ) is further taken into consideration, the accuracy of judgment as to whether or not the low viscosity fuel is being used is more accurate than that of the third embodiment of FIG. improves.

FIG. 33 shows the sixth embodiment and FIG. 2 of the third embodiment.
Corresponds to 5.

In this example, it is judged whether or not the low viscosity fuel is in use based on the ratio between the fluctuation amplitude ΔQ of the injection amount and the fluctuation amount ΔNe of the engine speed. As shown in FIG. Subsequent to the calculation, the rotation fluctuation amount ΔNe per unit time is calculated by the following formula: ΔNe = (Ne-Nem) / ΔT (8) where Ne: actual rotation speed Nem: moving average value of engine rotation speed ΔT: unit time (Step 131), | ΔQ | is set to the allowable value ε
1 and also | ΔNe | and the allowable value ε2 are compared (step 132 in FIG. 33). | ΔQ |> ε1 and | ΔNe |> ε
In the case of 2, the ratio F of the fluctuation amount of the injection amount and the rotation fluctuation amount is calculated as follows: F = a · | ΔQ | / b · | ΔNe | (9) where a and b are weighting factors (Steps 132 and 133 in FIG. 33), F
When the value of is larger than the threshold value F ₀ , it is determined that the low-viscosity fuel is being used, and the warning light is turned on (steps 134 and 81 in FIG. 33).

The weighting coefficient b is necessary in the equation (9) for the following reason. The rotation fluctuation amount ΔNe is small at the time of misfire and becomes large at the normal time, but the difference does not change greatly due to the bit. Therefore, if the weighting coefficient b is increased in order to magnify the change in ΔNe, | ΔQ
Since the value of | / b · | ΔNe | is small during normal operation and is large during misfire, the value of | ΔQ | / b · | ΔNe | is compared with the threshold value F _0, and If ΔNe | ≧ F _0, it can be determined that a misfire has occurred (that is, a low viscosity fuel is being used). The coefficient b is necessary to increase the difference between the misfire and the normal time.

On the other hand, due to the difference in injection pump, | ΔQ | /
Since the value of b · | ΔNe | changes, if the injection pump is different, the threshold value F ₀ must also be changed. Therefore, by introducing another weighting coefficient a and changing the value of the coefficient a for each injection pump, the threshold value F ₀ can be the same value regardless of the type of injection pump. This is the reason why the coefficient a is required.

In this example, it is possible to eliminate the influence of the rotational fluctuation that normally occurs due to the fluctuation of the engine load, etc., so that the accuracy of determining the fuel property is improved. For example, when the injection amount fluctuates due to the normal rotation fluctuation that may occur due to feedback control of the idle speed, or when the air conditioner is operated or the power steering is operated when the vehicle is stopped, etc., an auxiliary load is applied to the engine, which causes the idle speed When fluctuations occur, they are all normal operations, but in the first to fifth embodiments in which the rotation fluctuation amount ΔNe is not taken into consideration, it is also in these cases that low-viscosity fuel is being used. It cannot be said that there is a possibility of misjudgment. However, also in the first to fifth embodiments, it is needless to say that if the fluctuation signal of the injection amount is optimally processed and used, the fuel property can be accurately determined without considering the rotation fluctuation.

The oil pump for the power steering is always driven by the crankshaft while the engine is running, and when the power steering is stationary while the vehicle is stopped, the steering angle is equal to or more than a predetermined value and the oil pump for the engine is rotated. The load increases.

In the above six embodiments, the fuel property is judged based on the fluctuation amplitude ΔQ of the injection amount.
As shown in the upper part of FIG. 10, the fuel property can be determined based on the fluctuation amplitude of the TCV duty value (driving amount). Therefore, the injection amount in each of the first to sixth examples It is possible to replace the part for calculating the fluctuation amplitude of No. 1 and determining the fuel property based on the fluctuation amplitude with the part for calculating the fluctuation amplitude of the TCV duty value and judging the fuel property based on the fluctuation amplitude.

For example, FIG. 34 corresponds to FIG.
6 is an embodiment in which the fluctuation amplitude of the injection amount is replaced with the fluctuation amplitude of the TCV duty value in FIG.

34. Referring to FIG. 34, in step 142, the actual TCV duty value is obtained from the timer piston position Ctp by referring to the table having the contents shown in FIG. 35, and this is put into the variable D _REAL. Then, the fluctuation amplitude ΔD of the TCV duty value is calculated by the following equation: ΔD = (D _REAL −D _AV ) / ΔT (10) where D _{AV is} the moving average value of the TCV duty value ΔT: unit time.

The fluctuation amplitude ΔD and the threshold value D thus obtained
Th is compared in step 144, and if ΔD> Dth, it is determined that the low viscosity fuel is being used.

In FIG. 36, at step 151 ΔD
Is compared with the allowable value ε3, and | ΔNe | is compared with the allowable value ε2. When ΔD> ε3 and | ΔNe |> ε2, TCV
The ratio F between the fluctuation amplitude of the duty value and the rotation fluctuation amount is F2 = c · ΔD / b · | ΔNe | (11) where c and b are weighting factors (step 151 in FIG. 36, 152), F
When the value of 2 is larger than the threshold value F _0, it is determined that the low viscosity fuel is in use (step 153 in FIG. 36).

As shown in the examples of FIGS. 34 and 36, when the fuel property is judged based on the fluctuation amplitude of the TCV duty value during the feedback control of the injection timing during idling, the fuel injection amount of The control remains mechanical, and it can be applied to a so-called partial electronic control pump in which only the injection timing is electronically controlled by the timing control valve.

Finally, regarding the timing control valve 33 of FIG. 4, the leak flow rate from the high pressure chamber 28 increases as the TCV duty value decreases. The configuration that increases the leakage flow rate (that is, T
(The CV duty value is the ON time ratio of a fixed cycle)
It can also be applied to the timing control valve of. In this case, TCV can be
The duty value changes to the weight reduction side (see FIG. 10).
The upper side is the weight reduction side).

[0128]

According to the first aspect of the present invention, a distribution type injection pump in which the position of the control sleeve is adjusted according to the drive amount given to the actuator for driving the control sleeve,
A sensor for detecting the position of the control sleeve,
A means for calculating the basic injection amount matched with the reference fuel according to the engine speed and load, a means for feedback-correcting the injection amount so that the idle speed matches the target speed during idling, and this feedback Means for converting a corrected injection amount into a drive amount given to the control sleeve drive actuator; means for calculating an actual injection amount from a detection value of the control sleeve position sensor during feedback correction of the idle rotation; Means for calculating the average value from the injection quantity, means for calculating the fluctuation amplitude of the injection quantity from the average value and the actual injection quantity, and whether the reference fuel is used based on this fluctuation amplitude or low viscosity Since a means for determining whether the fuel is being used is provided, it is Course, since it is possible to determine to the misfire has occurred in the higher fuel temperature, not particularly require additional sensors, not be a cost.

In a second aspect based on the first aspect, the used fuel determination means comprises the variation amplitude of the injection amount and the variation cycle of the injection amount for two fuels, the reference fuel and the low viscosity fuel. A memory that stores a characteristic representing a frequency distribution of points, a unit that calculates the fluctuation cycle based on the actual injection amount when calculating the fluctuation amplitude, and a point that includes the calculated fluctuation cycle and the fluctuation amplitude. And a means for determining whether it belongs to the region of the reference fuel or the region of the low-viscosity fuel on the frequency distribution, further improving the accuracy of determination as to whether or not the low-viscosity fuel is in use. To do.

According to a third aspect of the present invention, in the first aspect of the present invention, the used fuel determination means calculates the rotational fluctuation amount of the engine when calculating the fluctuation amplitude, and the fluctuation amplitude and the rotational fluctuation amount. It is composed of a means for calculating a ratio and a means for determining whether the reference fuel is used or the low viscosity fuel is used by comparing the ratio with a threshold value. It is possible to eliminate the influence of the rotation fluctuation that is normally generated by the fluctuation of the engine load or the like by judging whether or not it is in use.

A fourth aspect of the present invention is a distribution type injection pump in which the flow rate of fuel bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by the drive amount given to the timing control valve, and the timer piston position. Sensor, a means for calculating the basic injection timing matched to the reference fuel according to the engine speed, a means for calculating the actual injection timing from the detection value of the timer piston position sensor, Means for feedback-correcting the drive amount applied to the timing control valve so that the actual injection timing coincides with the basic injection timing; and the timing from the detection value of the timer piston position sensor during the feedback correction of the injection timing at idle. Calculate the actual drive amount given to the control valve Means, a means for calculating an average value from the actual driving amount, a means for calculating a fluctuation amplitude of the driving amount from the average value and the actual driving amount, and the reference fuel is used based on the fluctuation amplitude. Since it is equipped with a means to determine whether the low-viscosity fuel is being used or the low-viscosity fuel is being used, it is of course possible to judge not only when the low-viscosity fuel is being used but also when a misfire has occurred due to an increase in the fuel temperature In addition, it does not require an additional sensor, and the control of the fuel injection amount remains mechanical due to cost constraints, and even for injection pumps in which only the injection timing is electronically controlled by the timing control valve. Can be applied.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the used fuel determination means comprises the variation amplitude of the drive amount and the variation period of the drive amount for two fuels, the reference fuel and the low viscosity fuel. A memory that stores a characteristic representing a frequency distribution of points, a unit that calculates the fluctuation cycle based on the actual driving amount when the fluctuation amplitude is calculated, and a point that includes the calculated fluctuation cycle and the fluctuation amplitude. And a means for determining whether it belongs to the region of the reference fuel or the region of the low-viscosity fuel on the frequency distribution, further improving the accuracy of determination as to whether or not the low-viscosity fuel is in use. To do.

According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the used fuel determination means calculates a rotational fluctuation amount of the engine when calculating the fluctuation amplitude, and the fluctuation amplitude and the rotational fluctuation amount. It is composed of a means for calculating a ratio and a means for determining whether the reference fuel is used or the low viscosity fuel is used by comparing the ratio with a threshold value. It is possible to eliminate the influence of the rotation fluctuation that is normally generated by the fluctuation of the engine load and the like from the judgment of whether or not it is in use, and the judgment accuracy of the fuel property improves.

A seventh aspect of the present invention is the means for issuing a warning according to any one of the first to sixth aspects, when the used fuel determination means determines that the low viscosity fuel is in use. Since the warning is provided, it is recognized that the fuel currently used is not suitable for operation from this warning, and if a reference fuel that is a fuel with a higher viscosity than the current fuel is added or the fuel is replaced with the reference fuel, It is possible to prevent deterioration of drivability due to misfire during idling.

In the eighth invention, the position of the control sleeve is adjusted according to the drive amount given to the control sleeve driving actuator, and the fuel flow rate which is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is timed. A distribution type injection pump adjusted by the drive amount given to the control valve, a means for calculating a basic injection timing matched with reference fuel according to the engine speed, and a sensor for detecting the control sleeve position, A means for calculating the basic injection amount matched with the reference fuel according to the engine speed and load, a means for feedback-correcting the injection amount so that the idle speed matches the target speed during idling, and this feedback The injection quantity to be used for driving the control sleeve Means for converting to a drive amount given to the actuator, means for calculating an actual injection amount from the detected value of the control sleeve position sensor during feedback correction of the idle rotation, and means for calculating an average value from the actual injection amount. , Means for calculating a fluctuation amplitude of the injection amount from the average value and the actual injection amount, and based on the fluctuation amplitude, it is determined whether the reference fuel is used or a low-viscosity fuel is used. And means for calculating a value obtained by advancing the basic injection timing when the low-viscosity fuel is used as the command injection timing, and when using the reference fuel, the basic injection timing is directly used as the command injection timing. Since the means for converting this command injection timing into the drive amount given to the timing control valve is provided, when using low-viscosity fuel Even when the fuel temperature increases, it is possible to reliably prevent a misfire during idling.

A ninth aspect of the invention is a distribution type injection pump in which the fuel flow rate of fuel bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by the drive amount given to the timing control valve, and the timer piston position. Sensor, a means for calculating the basic injection timing matched to the reference fuel according to the engine speed, a means for calculating the actual injection timing from the detection value of the timer piston position sensor, Means for feedback-correcting the drive amount given to the timing control valve so that the actual injection timing coincides with the command injection timing; and the timing control from the detection value of the timer piston position sensor during the feedback correction of the injection timing at the time of idling. Calculate the actual drive amount given to the valve Stage, means for calculating an average value from the actual driving amount, means for calculating a fluctuation amplitude of the driving amount from the average value and the actual driving amount, and the reference fuel is used based on the fluctuation amplitude. Whether the low-viscosity fuel is used or not, and when the low-viscosity fuel is used from this determination result, the value obtained by advancing the basic injection timing is used as the command injection timing, and the reference fuel is used. Since the means for calculating the basic injection timing as it is as the command injection timing is provided at times, misfire at idle can be surely prevented even when the fuel temperature rises when low-viscosity fuel is used.

In a tenth aspect of the invention, the position of the control sleeve is adjusted in accordance with the drive amount given to the control sleeve drive actuator, and the fuel flow rate that is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is the timing. A distribution type injection pump that is adjusted by the drive amount given to the control valve, a means for calculating the basic injection timing that matches the reference fuel according to the engine speed, and a learning value for the advance correction amount of the injection timing. For storing the value of the memory even after the engine is stopped, a sensor for detecting the position of the control sleeve, and a basic injection amount matching the reference fuel depending on the engine speed and load. And the idle speed is equal to the target speed at idle. Means for feedback-correcting the injection amount, means for converting the feedback-corrected injection amount into a drive amount to be given to the control sleeve driving actuator, and a control sleeve position sensor during the idle rotation feedback correction. A means for calculating the actual injection amount from the detected value, a means for calculating an average value from the actual injection amount, a means for calculating the variation amplitude of the injection amount from the average value and the actual injection amount, and the variation amplitude Based on the means for determining whether the reference fuel is being used or the low-viscosity fuel is being used, based on this determination result, when the low-viscosity fuel is used, the basic injection timing is advanced and corrected with the learning value. The value is used as the command injection timing, and when the reference fuel is used, the basic injection timing is used as it is as the command injection timing. Means for output, and means for searching for means for converting the driving amount giving the command injection timing to the timing control valve, the advance angle correction amount at the misfire timing based on the fluctuation amplitude,
Since the means for determining the value obtained by adding the allowance allowance to the advanced angle correction amount at the searched misfire timing as the learning value is provided, the learning value is determined at the previous operation using the low viscosity fuel, If the low-viscosity fuel is used during this operation as well, the learning value will be added stepwise to the basic injection timing from the timing of the idle state after the start, and the start will start with the low-viscosity fuel. When you do, you can surely prevent misfire.

An eleventh aspect of the invention is a distribution type injection pump in which the fuel flow rate of fuel bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by the drive amount given to the timing control valve, and the timer piston position. Sensor, a means for calculating the basic injection timing matching the reference fuel according to the engine speed, a memory for storing the learning value of the advance correction amount of the injection timing, and the value of this memory A means for backing up even after the engine is stopped, a means for calculating the actual injection timing from the detection value of the timer piston position sensor, and a drive for giving the timing control valve such that the actual injection timing coincides with the command injection timing at the time of idling. The amount of feedback correction and the amount of drive Means for outputting to the timing control valve, means for calculating the actual drive amount given to the timing control valve from the detection value of the timer piston position sensor during the feedback correction of the injection timing at the time of idling, and the average from the actual drive amount A means for calculating the value, a means for calculating the fluctuation amplitude of the driving amount from the average value and the actual injection amount, and whether the reference fuel is used based on this fluctuation amplitude or a low-viscosity fuel is used. And a value obtained by advancing the basic injection timing with the learning value when the low-viscosity fuel is used based on this determination result, and the basic injection timing when the reference fuel is used. Is calculated as the command injection timing as it is, and the advance angle compensation at the misfire timing is performed based on the fluctuation amplitude. Since the means for searching the amount and the means for determining the value obtained by adding the margin allowance to the advanced correction amount at the searched misfire timing as the learning value are provided, the previous operation using the low viscosity fuel is performed. When the learning value is determined at the time and the low-viscosity fuel is continuously used during this operation as well, the learning value will be added stepwise to the basic injection timing from the timing of the idle state after the start, Even when starting the engine with the low-viscosity fuel, misfire can be reliably prevented.

In a twelfth aspect of the invention, in any one of the eighth aspect to the eleventh aspect of the invention, the advance angle correction is canceled after a certain time has elapsed even after the injection angle is corrected in advance. Then, the fuel property is re-evaluated, so that it is possible to cope with the change in the fuel property after the injection timing is advanced and corrected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a fuel injection pump.

FIG. 2 is a perspective view of a rotary solenoid.

FIG. 3 is a diagram showing a positional relationship between a rotary shaft of a rotary solenoid and a control sleeve.

FIG. 4 is a sectional view of a timer portion.

FIG. 5 is a control system diagram of an electronically controlled injection pump.

FIG. 6 is a flowchart for explaining feedback control of idle rotation.

FIG. 7 is a characteristic diagram of a basic injection amount Qt.

FIG. 8 is a characteristic diagram of an injection amount feedback correction amount DQ.

FIG. 9 is a characteristic diagram of a duty value Drot given to a rotary solenoid.

FIG. 10 is a waveform diagram showing a simplified model of each variation of the injection amount and the TCV duty value that occurs at the time of misfire.

FIG. 11 is a flow chart for explaining why an increase amount fluctuation of the injection amount occurs at the time of misfire.

FIG. 12 is a flowchart for explaining why an increase side fluctuation of the TCV duty value occurs at the time of misfire.

FIG. 13 is a flow chart for explaining the fuel property determination and the injection timing correction control using the determination result.

FIG. 14 is a characteristic diagram of a basic injection timing IT.

FIG. 15 is a characteristic diagram of an actual injection amount Q _REAL .

FIG. 16 is a flowchart for explaining calculation of a moving average value Q _AV of the injection amount.

FIG. 17 is a flow chart for performing feedback control of injection timing.

FIG. 18 is a characteristic diagram of the basic value DTY of the TCV duty value.

FIG. 19 is a characteristic diagram of actual injection timing IT _REAL .

FIG. 20 is a characteristic diagram of a feedback correction amount DDTY of a TCV duty value.

FIG. 21 is a flow chart for explaining the determination of the fuel property and the correction control of the injection timing using the determination result of the second embodiment.

22 is a flowchart for explaining the subroutine of step 54 of FIG. 21. FIG.

FIG. 23 is a waveform diagram for explaining determination of a learning value ITg according to the second embodiment.

FIG. 24 shows the learning value ITg determined during the previous operation using the low-viscosity fuel, and the low-viscosity fuel is also used during the current operation, at the timing of the idle state after the start. It is a waveform diagram for explaining how the learning value ITg is added.

FIG. 25 is a flow chart for explaining the judgment of the fuel property and the warning using the judgment result of the third embodiment.

FIG. 26 is a flow chart for explaining the judgment of the fuel property and the warning using the judgment result of the fourth embodiment.

FIG. 27 is a flowchart for explaining calculation of a cumulative value ΔQsum of fluctuation amplitudes in the fourth example.

FIG. 28 is a waveform chart for explaining the operation of the fourth embodiment.

FIG. 29 is a flow chart for explaining the judgment of the fuel property and the warning using the judgment result in the fifth embodiment.

FIG. 30 is a flowchart for explaining calculation of a moving average value T _AV of a fluctuation period and coupling of the average value T _AV and the fluctuation amplitude ΔQ in the fifth embodiment.

FIG. 31 is a characteristic diagram showing the frequency distribution of the fluctuation amplitude and fluctuation cycle of the injection amount in the fifth embodiment.

FIG. 32 is a waveform chart for explaining changes in the fluctuation cycle of the fifth embodiment.

FIG. 33 is a flow chart for explaining the judgment of the fuel property and the warning using the judgment result in the sixth embodiment.

FIG. 34 is a flow chart for explaining the judgment of the fuel property and the warning using the judgment result of the seventh embodiment.

FIG. 35 is an actual TCV duty value D _{REAL of} the seventh embodiment.
FIG.

FIG. 36 is a flow chart for explaining the judgment of the fuel property and the warning using the judgment result of the eighth embodiment.

FIG. 37 is a diagram corresponding to the claim of the first invention.

FIG. 38 is a diagram corresponding to the claim of the second invention.

FIG. 39 is a diagram corresponding to the claim of the third invention.

FIG. 40 is a diagram corresponding to the claim of the fourth invention.

FIG. 41 is a diagram corresponding to the claim of the fifth invention.

FIG. 42 is a diagram corresponding to the claim of the sixth invention.

FIG. 43 is a diagram corresponding to the claim of the eighth invention.

FIG. 44 is a diagram corresponding to the claim of the ninth invention.

FIG. 45 is a diagram corresponding to the claim of the tenth invention.

FIG. 46 is a diagram corresponding to the claim of the eleventh invention.

[Explanation of symbols]

16 Control Sleeve 21 Rotary Solenoid (Actuator for Control Sleeve Drive) 26 Timer Piston 33 Timing Control Valve 35 Control Unit 36 Accelerator Sensor 38 Control Sleeve Position Sensor 39 Timer Piston Position Sensor 52 Control Sleeve Drive Actuator 53 Timing Control Valve 54 Control Sleeve Position Sensor 55 Basic injection amount calculation means 56 Idle rotation feedback correction means 57 Drive amount conversion means 58 Actual injection amount calculation means 59 Average value calculation means 60 Fluctuation amplitude calculation means 61 Used fuel determination means 71 Frequency distribution memory 72 Fluctuation cycle calculation means 73 Area Judgment means 81 Rotational fluctuation amount calculation means 82 Ratio calculation means 83 Comparison means 9 Timer piston position sensor 92 Basic injection timing calculation means 93 Actual injection timing calculation means 94 Drive amount feedback correction means 96 Actual drive amount calculation means 97 Average value calculation means 98 Fluctuation amplitude calculation means 99 Used fuel determination means 101 Frequency distribution memory 102 Fluctuation cycle Calculation means 103 Region determination means 111 Ratio calculation means 112 Comparison means 121 Command injection timing calculation means 122 Drive amount conversion means 131 Drive amount feedback correction means 141 Learning value memory 142 Backup means 143 Command injection timing calculation means 144 Misfire timing search means 145 Learning Value determining means 151 Misfire timing searching means 152 Learning value determining means

Claims (12)

[Claims] 1. A distribution type injection pump in which a control sleeve position is adjusted according to a driving amount given to a control sleeve driving actuator, a sensor for detecting the control sleeve position, and a basic injection matching a reference fuel. Means for calculating the amount according to the engine speed and load, means for feedback-correcting the injection amount so that the idle speed matches the target speed during idling, and the feedback-corrected injection amount for the control sleeve Means for converting into a drive amount given to a drive actuator, means for calculating an actual injection amount from a detection value of the control sleeve position sensor during feedback correction of the idle rotation, and means for calculating an average value from the actual injection amount From this average value and the actual injection amount Diesel characterized by providing a means for calculating a fluctuation amplitude of the injection amount and a means for judging whether the reference fuel is used or a low-viscosity fuel is used based on the fluctuation amplitude Engine fuel property detection device. 2. The used fuel determination means stores a characteristic representing a frequency distribution of points consisting of the fluctuation amplitude of the injection amount and the fluctuation cycle of the injection amount for the two fuels of the reference fuel and the low viscosity fuel. And a means for calculating the fluctuation cycle based on the actual injection amount when calculating the fluctuation amplitude, and a point composed of the calculated fluctuation cycle and the fluctuation amplitude of the reference fuel on the frequency distribution. 2. The fuel property detection device for a diesel engine according to claim 1, further comprising: means for determining whether the fuel belongs to a region or a region of the low-viscosity fuel. 3. The used fuel determination means, means for calculating an engine rotation fluctuation amount when calculating the fluctuation amplitude,
Means for calculating the ratio of the fluctuation amplitude and the rotation fluctuation amount;
The diesel engine according to claim 1, further comprising means for determining whether the reference fuel is used or the low-viscosity fuel is used by comparing the ratio with a threshold value. Fuel property detector. 4. A distribution type injection pump in which the flow rate of fuel that is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by the drive amount given to the timing control valve, and a sensor that detects the position of the timer piston. A means for calculating the basic injection timing matched to the reference fuel according to the engine speed, a means for calculating the actual injection timing from the detection value of the timer piston position sensor, and a means for calculating the actual injection timing at idle. Means for feedback-correcting the drive amount given to the timing control valve so as to match the basic injection timing; and giving to the timing control valve from the detection value of the timer piston position sensor during the feedback correction of the injection timing at idle. A means to calculate the actual drive amount Means for calculating an average value from the actual driving amount, means for calculating a fluctuation amplitude of the driving amount from the average value and the actual driving amount, and whether the reference fuel is used based on the fluctuation amplitude. A fuel property detection device for a diesel engine, comprising: means for determining whether low-viscosity fuel is being used. 5. The characteristic used by the used fuel determination means stores a frequency distribution of points consisting of the fluctuation amplitude of the driving amount and the fluctuation period of the driving amount for two fuels, the reference fuel and the low viscosity fuel. Memory, means for calculating the fluctuation cycle based on the actual drive amount when calculating the fluctuation amplitude, and a point consisting of the calculated fluctuation cycle and the fluctuation amplitude of the reference fuel on the frequency distribution. 5. The fuel property detecting device for a diesel engine according to claim 4, further comprising means for determining whether it belongs to a region or a region of the low viscosity fuel. 6. The means for determining fuel consumption, means for calculating an amount of rotation fluctuation of an engine when calculating the fluctuation amplitude,
Means for calculating the ratio of the fluctuation amplitude and the rotation fluctuation amount;
5. The diesel engine according to claim 4, further comprising means for determining whether the reference fuel or the low viscosity fuel is used by comparing the ratio with a threshold value. Fuel property detector. 7. The method according to claim 1, further comprising means for issuing a warning when the used fuel determination means determines that the low viscosity fuel is being used. The fuel property detection device for a diesel engine according to 1. 8. The control sleeve position is adjusted according to the drive amount given to the control sleeve drive actuator, and the fuel flow rate that is bypassed from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is given to the timing control valve. A distribution type injection pump that is adjusted by the drive amount, a means that calculates the basic injection timing that matches the reference fuel according to the engine speed, a sensor that detects the control sleeve position, and a reference fuel Means for calculating the basic injection quantity matched according to the engine speed and load, means for feedback-correcting the injection quantity so that the idle speed matches the target speed during idling, and this feedback injection quantity The control sleeve drive actuator Means for converting to a drive amount given to the engine, means for calculating an actual injection amount from the detection value of the control sleeve position sensor during feedback correction of the idle rotation, means for calculating an average value from the actual injection amount, Means for calculating the fluctuation amplitude of the injection quantity from the average value and the actual injection quantity, and means for judging whether the reference fuel or the low-viscosity fuel is used based on the fluctuation amplitude And a means for calculating a value obtained by advancing the basic injection timing when the low-viscosity fuel is used, as the command injection timing, and calculating the basic injection timing as the command injection timing when the reference fuel is used. And a means for converting a command injection timing into a drive amount given to the timing control valve. Injection timing control device. 9. A distribution type injection pump, in which the flow rate of fuel that is bypassed from a high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by the drive amount given to a timing control valve, and a sensor that detects the position of the timer piston. A means for calculating the basic injection timing matched to the reference fuel according to the engine speed, a means for calculating the actual injection timing from the detection value of the timer piston position sensor, and a means for calculating the actual injection timing at idle. A means for feedback-correcting the drive amount applied to the timing control valve so as to match the command injection timing; and an actual value applied to the timing control valve from the detection value of the timer piston position sensor during the feedback correction of the injection timing at idle. A means for calculating the drive amount, Means for calculating an average value from the actual driving amount, means for calculating a fluctuation amplitude of the driving amount from the average value and the actual driving amount, and whether the reference fuel is used based on the fluctuation amplitude or a low value. A means for determining whether or not the viscous fuel is used, and a value obtained by advancing the basic injection timing when the low-viscosity fuel is used based on this determination result is the command injection timing, and when using the reference fuel, the basic injection An injection timing control device for a diesel engine, comprising: means for calculating the timing as the command injection timing as it is. 10. A control sleeve position is adjusted according to a drive amount given to a control sleeve driving actuator, and a fuel flow rate which is bypassed from a high pressure chamber at one end of a timer piston and leaked to a low pressure side is given to a timing control valve. Distributor type injection pump adjusted by drive amount, means for calculating basic injection timing matching with reference fuel according to engine speed, and memory for storing learning value of advance correction amount of injection timing And a means for backing up the value of this memory even after the engine is stopped, a sensor for detecting the position of the control sleeve, and a means for calculating a basic injection amount matching the reference fuel according to the engine speed and load. When idling, make sure that the idle speed matches the target speed. Means for feedback-correcting the injection quantity, means for converting the feedback-corrected injection quantity into a drive quantity given to the control sleeve drive actuator, and a value detected by the control sleeve position sensor during feedback correction of the idle rotation. Means for calculating an actual injection amount, means for calculating an average value from the actual injection amount, means for calculating a variation amplitude of the injection amount from the average value and the actual injection amount, and A means for determining whether the reference fuel is used or the low-viscosity fuel is used, and based on this determination result, when the low-viscosity fuel is used, the value obtained by correcting the advance angle of the basic injection timing with the learning value is commanded. As the injection timing, and when using the reference fuel, the basic injection timing is directly calculated as the command injection timing. Means, means for converting the command injection timing into a drive amount given to the timing control valve, means for searching the advance angle correction amount at the misfire timing based on the fluctuation amplitude, and means for searching the misfire timing. An injection timing control device for a diesel engine, comprising: means for determining a value obtained by adding a margin allowance to the advance angle correction amount as the learning value. 11. A distribution type injection pump, in which a fuel flow rate that is bypassed from a high pressure chamber at one end of a timer piston and leaked to a low pressure side is adjusted by a drive amount given to a timing control valve, and a sensor for detecting a position of the timer piston. And a means for calculating the basic injection timing matched to the reference fuel according to the engine speed, a memory for storing the learning value of the advance correction amount of the injection timing, and the value of this memory after the engine is stopped. And a means for calculating the actual injection timing from the detected value of the timer piston position sensor, and a feedback correction of the drive amount given to the timing control valve so that the actual injection timing coincides with the commanded injection timing during idling. Means for controlling the feedback correction drive amount Means for outputting to the control valve, means for calculating the actual drive amount given to the timing control valve from the detected value of the timer piston position sensor during the feedback correction of the injection timing at the time of idling, and the average from the actual drive amount. A means for calculating the value, a means for calculating the fluctuation amplitude of the driving amount from the average value and the actual injection amount, and whether the reference fuel is used or a low viscosity fuel is used based on the fluctuation amplitude. Means for determining whether the fuel is low in viscosity, the value obtained by advancing the basic injection timing with the learning value is used as the command injection timing when the low-viscosity fuel is used, and the basic injection timing is used when the reference fuel is used. Is calculated as the command injection timing as it is, and the advance correction amount at the misfire timing is calculated based on the fluctuation amplitude. Means for search, the injection timing control device for a diesel engine, wherein a value obtained by adding a margin is provided and means for determining as the learning value to the advance correction amount in the searched misfire timing. 12. The fuel property is re-evaluated by canceling the advance correction after a predetermined time has elapsed even after the injection timing is corrected.
An injection timing control device for a diesel engine according to any one of items 1 to 5.