JP3348539B2 - Fuel property detection device and injection timing control device for diesel engine - Google Patents

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 an injection timing control.

[0002]

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

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

[0004]

By the way, when the basic injection amount and the basic injection timing are matched with a reference fuel such as JIS No. 2 light oil, the basic injection amount and the basic injection time are adjusted to the use environment in a cold region such as JIS special No. 3 light oil. When low-viscosity fuel is used, the injection timing is substantially delayed due to a decrease in the pump efficiency of the feed pump inside the pump and an increase in the amount of leakage in the plunger pumping stroke.This low-viscosity fuel is used in summer. When this is done, the fuel viscosity further decreases as the outside air temperature rises. This further decrease in viscosity leads to frequent misfires especially during idling, resulting in poor drivability during idling.

In this case, during the feedback control of the idle speed by using the low-viscosity fuel, a phenomenon occurs in which the injection amount increases while the idle speed is kept constant. Utilizing this phenomenon, a technique for judging that a low-viscosity fuel is being used when the feedback amount of the injection amount exceeds a predetermined value has been previously applied (see Japanese Patent Application No. 5-235215). .

However, since the prior application does not detect whether a misfire has occurred, it is insufficient to reliably prevent the occurrence of a misfire when the fuel temperature rises when using a low-viscosity fuel.

[0007] Therefore, the present invention captures a specific phenomenon at the time of misfire and determines whether or not a low-viscosity fuel is used, so that misfire when the fuel temperature rises during use of the low-viscosity fuel can be ensured. The purpose is to prevent.

[0008]

According to a first aspect of the present invention, as shown in FIG. 37, the position of the control sleeve is adjusted according to the amount of drive applied to a control sleeve drive actuator (for example, a rotary solenoid) 52. An 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 the reference fuel according to the engine speed and load, and an idle speed at the time of idling. Means 56 for feedback-correcting the injection quantity so as to match the rotation speed, means 57 for converting the feedback-corrected injection quantity Q into a drive quantity to be given to the control sleeve driving actuator 52, and 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
Means 59 for calculating _AV , means 6 for calculating the fluctuation amplitude ΔQ of the injection amount from the average value Q _AV and the actual injection amount Q _REAL 6
Means 61 for determining whether the reference fuel or the low-viscosity fuel is used based on 0 and the fluctuation amplitude ΔQ is provided.

According to a second aspect of the present invention, in the first aspect, as shown in FIG. 38, the used fuel judging means 61 performs the above-described variation of the injection amount for two fuels, the reference fuel and the low-viscosity fuel. A memory 71 for storing a characteristic representing a frequency distribution of points consisting of the amplitude ΔQ and the fluctuation period T _{AV of the} injection amount.
When calculating the fluctuation amplitude ΔQ, the actual injection amount Q
Means 72 for calculating the fluctuation period T _AV based on _REAL
Means 73 for determining whether a point consisting of the calculated fluctuation cycle T _AV and the fluctuation amplitude ΔQ belongs to the area of the reference fuel or the area of the low-viscosity fuel on the frequency distribution. .

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

According to a fourth aspect of the present invention, as shown in FIG. 40, the amount of fuel leaked from the high-pressure chamber at one end of the timer piston to the low-pressure side by the drive amount (eg, duty value) given to the timing control valve 53 A dispensing-type 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 corresponding to a reference fuel according to the engine speed; Means 93 for calculating the actual injection timing IT _REAL from the detection value of the sensor 91, and 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, during said feedback correction of the injection timing at idle, From the detection value of the timer piston position sensor 91, the timing control valve 5
A means 96 for calculating an actual driving amount D _REAL given to 3, the means 97 for calculating an average value D _AV from the actual driving amount D _REAL,
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. Means 99 for judging whether or not they have been performed.

According to a fifth aspect of the present invention, in the fourth aspect, as shown in FIG. 41, the used fuel judging means 99 is provided for controlling 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 composed of an amplitude ΔD and a variation period T _{AV of a} drive amount.
The actual drive amount D when calculating the fluctuation amplitude ΔD.
Means 10 for calculating the fluctuation period T _AV based on _REAL
And a means 103 for determining whether a point consisting of the calculated fluctuation cycle T _AV and the fluctuation amplitude ΔD belongs to the area of the reference fuel or the area of the low-viscosity fuel on the frequency distribution. I do.

According to a sixth aspect, in the fourth aspect, as shown in FIG. 42, when the used fuel determination means 99 calculates the variation amplitude ΔD, the engine rotation variation 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.
Means 112 for comparing the ratio ΔD / ΔNe with a threshold to determine whether the reference fuel is used or the low-viscosity fuel is used.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the used fuel judging means 6 is provided.
A means is provided for issuing a warning when it is determined by 1,99 that the low-viscosity fuel is being used.

According to an eighth aspect of the present invention, as shown in FIG. 43, the control sleeve position is controlled by a control sleeve driving actuator (for example, a rotary solenoid) 5.
2 is adjusted according to the drive amount given to the timing control valve 53, and the flow rate of fuel leaked to the low pressure side by bypassing from the high pressure chamber at one end of the timer piston is adjusted.
A distribution-type injection pump that is adjusted by a drive amount (for example, a duty value) given to the engine; a means 92 for calculating a basic injection timing IT matched with a reference fuel according to the engine speed; 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 the load, and an injection amount such that the idle speed matches the target speed during idling. Means 56 for correcting the feedback, and the injection amount Q fed back to the control sleeve driving actuator 52
Means 58 for converting the actual injection amount Q _REAL from the detected value of the control sleeve position sensor 54 during the feedback correction of the idling rotation, and an average value from the actual injection amount Q _REAL. Means 59 for calculating Q _AV , the average value Q _AV and the actual injection quantity Q
Means 60 for calculating fluctuation amplitude ΔQ of injection amount from _REAL
Means 61 for determining whether the reference fuel or low-viscosity fuel is being used based on the fluctuation amplitude ΔQ. Based on the determination result, the basic injection timing IT Is used as the command injection timing IT _SET , and when the reference fuel is used, the basic injection timing IT is used as it is as the command injection timing IT _SET.
Means 121 for calculating as _SET , and the command injection timing I
Means 122 for converting T _SET into a drive amount given to the timing control valve 53.

According to a ninth aspect of the present invention, as shown in FIG. 44, the flow rate of the fuel leaked to the low pressure side by bypassing from the high pressure chamber at one end of the timer piston depends on the drive amount (eg, duty value) given to the timing control valve 53. A dispensing-type 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 corresponding to a reference fuel according to the engine speed; Means 93 for calculating the actual injection timing IT _REAL from the detection value of the sensor 91, and 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 during idling 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
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 ;
Means 9 for determining whether said reference fuel or low viscosity fuel is being used based on D
9, when the low-viscosity fuel is used, the value obtained by advancing the basic injection timing IT is used as the command injection timing I.
A means 121 is provided for calculating the basic injection timing IT as the command injection timing IT _SET as T _SET and when the reference fuel is used.

According to a tenth aspect, as shown in FIG.
The control sleeve position is the actuator that drives the control sleeve (for example, a rotary solenoid)
The timing control valve 5 adjusts the flow rate of the fuel to be adjusted in accordance with the drive amount given to the valve 52 and to leak from the high-pressure chamber at one end of the timer piston to the low-pressure side.
3, a distribution type injection pump that is adjusted by a drive amount (for example, a duty value) given to the fuel injection unit 3, a means 92 for calculating a basic injection timing IT matched with the reference fuel according to the engine speed, and a progress of the injection timing. A memory 141 for storing a learning value ITg of the angle correction amount;
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 a basic injection amount Qt matched with the reference fuel according to the engine speed and load.
And means 56 for feedback-correcting the injection amount so that the idling speed matches the target speed during idling.
Means 57 for converting the injection amount Q to be feedback-corrected into a drive amount to be applied to the control sleeve driving actuator 52, and an actual injection amount based on the detected value of the control sleeve position sensor 54 during the feedback correction of the idle rotation. Means 5 for calculating Q _REAL
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; based on the determination result, when the low-viscosity fuel is used, the basic injection timing IT is set to the learning value as advance correction value of the command injection timing IT _SET at ITG, also when using the reference fuel is a means 143 for calculating the IT said basic injection timing as it is a command injection timing IT _SET, the timing control this command injection timing IT _SET Means 122 for converting into a drive amount to be applied to the valve 53;
Means 144 for searching the advance correction amount ITc at the misfire timing based on Q, and means for determining a value obtained by adding the allowance ITp to the searched advance correction amount ITc at the misfire timing as the learning value ITg. 145 were provided.

In the eleventh invention, as shown in FIG.
A distribution type injection pump in which the flow rate of fuel leaked to the low pressure side from the high pressure chamber at one end of the timer piston is adjusted by a drive amount (for example, a 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 the reference fuel according to the engine speed, a memory 141 for storing a learning value ITg of the advance correction amount of the injection timing, and this memory 141. 142 for backing up the value after the engine is stopped, means 93 for calculating the actual injection timing IT _REAL from the detection value of the timer piston position sensor 91, and the actual injection timing IT _REAL at idle when the command injection timing IT _REAL
Means 1 for feedback-correcting the drive amount given to the timing control valve 53 so as to coincide with _SET.
And 31, a means 96 for calculating an actual driving amount D _REAL providing from the detected value of said timer piston position sensor 91 in said feedback correction of the injection timing at idle on the timing control valve 53, the actual driving amount D
A means 97 for calculating an average value D _AV from _REAL, variations in driving amount from the average value D _AV said the actual injection quantity Q _REAL amplitude ΔD
98, a means 99 for determining whether the reference fuel is used or a low-viscosity fuel is used based on the fluctuation amplitude ΔD. The basic injection timing IT
A means 143 for calculating the advance correction value by the learning value ITg as IT _SET the command injection timing and the basic injection timing IT when using the reference fuel as it is the command injection timing IT _SET, said variation amplitude ΔD Means 151 for searching the advance correction amount ITc at the misfire timing based on the calculated value ITc and the value obtained by adding the margin ITp to the searched advance correction amount ITc at the misfire timing.
means 152 for determining g.

According to a twelfth invention, in any one of the eighth invention to the eleventh invention, the advance correction is canceled after a lapse of a predetermined time after the injection timing is advanced. And re-evaluate the fuel properties.

[0020]

According to the first aspect of the present invention, since the fuel property is determined based on the fluctuation amplitude ΔQ of the injection amount, it is determined not only that a low-viscosity fuel is being used but also that misfire has occurred due to an increase in fuel temperature. can do.

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

In the second aspect of the present invention, even if the fluctuation amplitude ΔQ of the injection amount is the same value, the fluctuation period is further taken into account, so that the accuracy of determining whether or not the fuel is low viscosity fuel is further improved.

According to the third aspect of the present invention, the influence of the rotation fluctuation that normally occurs due to 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 that the accuracy of the fuel property judgment is improved. .

In the fourth invention, the fuel property is determined based on the fluctuation amplitude ΔD of the drive amount. Therefore, it is determined not only that a low-viscosity fuel is being used but also that misfire has occurred due to an increase in fuel temperature. And no additional sensors are required.

When judging the fuel property based on the fluctuation amplitude of the drive amount, the control of the fuel injection amount remains mechanical due to cost restrictions, and the electronic control is performed only on the injection timing by the timing control valve. The present invention can also be applied to a conventional injection pump.

In the fifth aspect of the present invention, even when the fluctuation amplitude ΔD of the driving amount is the same value, the fluctuation period is further taken into account, so that the accuracy of determining whether or not the fuel is low viscosity fuel is further improved.

According to the sixth aspect of the present invention, since the influence of the rotation fluctuation normally occurring due to the fluctuation of the engine load or the like is removed from the judgment as to whether or not the low-viscosity fuel is being used, the accuracy of the fuel property judgment is improved. .

In the seventh aspect, the driver is notified by the warning that the currently used fuel is not suitable for driving, so that the reference fuel having a higher viscosity than the current fuel can be added or the fuel can be added. By replacing with the reference fuel, deterioration of drivability due to misfire during idling can be prevented.

According to the eighth aspect of the invention, the injection timing is advanced when the low-viscosity fuel is used and misfire occurs due to an increase in fuel temperature, so that misfire during idling is reliably prevented. .

Also in the ninth invention, the injection timing is advanced when the low-viscosity fuel is used and misfire occurs due to an increase in fuel temperature, so that misfire during idling is reliably prevented. .

In the tenth aspect, the learning value ITg is determined during the previous operation using the low-viscosity fuel, and the low-viscosity fuel is also used during the current operation. The basic injection timing (I
The learning value ITg is added stepwise to T),
Even when starting with a low-viscosity fuel, misfire is reliably prevented.

In the eleventh invention as well, the learning value ITg is determined during the previous operation using the low-viscosity fuel, and the low-viscosity fuel is also used during the current operation. The basic injection timing (I
The learning value ITg is added stepwise to T),
Even when starting with a low-viscosity fuel, misfire is reliably prevented.

According to the twelfth aspect, it is possible to cope with a change in fuel properties after the injection timing is advanced.

[0034]

FIG. 1 shows an electronically controlled distribution type fuel injection pump.
It is known.

First, fuel is sucked from an inlet (not shown) of the pump body by a feed pump 3 driven by a drive shaft (connected to an engine output shaft) 2, and the fuel guided to a pump chamber 5 is operated. At the same time as the lubrication of the part is performed, 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 disk 9 connected to the drive shaft 2,
Driven by the drive shaft 2 via the joint 2A in synchronization with engine rotation. The cam disc 9 has a number of cylinders as many full E Isukamu 10 of the engine, each time to overcome the roller 12 arranged on the roller ring 11 while rotating the face cam 10 is reciprocated by a predetermined cam lift.

As described above, when the plunger 8 reciprocates while rotating, the fuel sucked from the suction port 6 is pressure-fed from the distribution port 13 through the delivery valve 14 to the injection nozzle (not shown) by the reciprocation. You.

On the other hand, the amount of fuel injected is determined by the position of the control sleeve 16 covering the cut-off port 15 formed in the plunger 8. For example, when the opening of the cut-off port 15 moves to the right of the plunger 8 and passes over the right end of the control sleeve 16, the fuel that has been pumped from the plunger high-pressure chamber 7A to the distribution port 13 up to that point is moved. , Cut-off port 1
5 and is released to the low-pressure pump chamber 5, so that the pumping to the distribution port 13 is terminated.

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

The control sleeve 16 is supported by a ball 23 provided eccentrically at the tip of a rotor (rotary shaft) 22 of a rotary solenoid (a kind of proportional solenoid) 21 and is controlled in accordance with 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 a 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 in the right direction (the amount of fuel injection increases), the rotation angle of the rotor 22 in the clockwise direction is increased in proportion to the duty value (ON time ratio per fixed time) given to the rotary solenoid 21. I'm trying to get bigger.

The fuel injection timing is adjusted by changing the relative position between 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 guided to the high pressure chamber 28 at one end of the timer piston 26 sliding in the cylinder 27 through the passage 29, and the low pressure chamber 3 on the opposite side.
0 is close to a negative pressure by communicating with the suction side of the feed pump 3, but the timer piston 26 is pushed back by the elastic force of the spring 31.

When the fuel pressure in the pump chamber 5 rises due to the increase in engine speed, the timer piston 30 is pushed rightward in FIG. 4, thereby rotating the roller ring 11 in the direction opposite to the rotation of the cam disk 8. , So that the injection timing is relatively advanced. Face cam 10 of cam disk 9
When the roller ring 11 is rotated in the direction opposite to the rotation direction of the cam disk 9, fuel is injected when the roller 1 rides on the roller 12.
Thus, the timing for riding on the vehicle 2 becomes earlier, so that the fuel injection timing with respect to the crank angle can be advanced.

However, the fuel pressure in the pump chamber 5 is
Since the injection timing linearly increases in proportion to the engine speed, the injection timing can basically be linearly advanced in proportion to the engine speed. Therefore, if the fuel in the high-pressure chamber 28 leaks 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 a duty value (hereinafter, referred to as a 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 maximum advance angle is obtained when the timing control valve 33 is in the fully closed position, and the minimum advance angle (the leakage flow rate to the low pressure side is maximum) at 0% (when the timing control valve is in the fully open position). OFF time ratio is 100%
That is, the timing control valve is in a non-energized state, and the timing control valve is in the fully closed position in the non-energized state 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 no timing control valve is provided).

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

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

The reference pulse is one pulse per rotation of the injection pump, and the scale pulse is 36 pulses per rotation 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 accelerator opening, water temperature sensor 4
0, together with signals from an air conditioner switch 41 and an inhibitor switch 42 for detecting a selector position of the automatic transmission, are input to the control unit 35.
The drive amount given to the rotary solenoid 21 and the timing control valve 33 is controlled together. Note that, based on the two reference pulses and the scale pulse from the injection pump, the control unit 35
Needless to say, the pump rotation speed is calculated within the range, and the engine rotation speed (twice the pump rotation speed) Ne is further calculated from the pump rotation speed.

FIG. 6 is a flow chart for explaining the feedback control of the idling speed.
0 to 50 msec).

In FIG. 6, the engine speed Ne and the accelerator opening (accelerator pedal opening) CL are read in step 1, and the basic injection amount is read from these values in step 2 with reference to the map shown in 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).

In step 3, it is determined whether the vehicle is idling or not.
If idle, it is determined that the condition is a feedback condition, and the process proceeds to steps 4 to 7.

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

In steps 5, 6 and 7, the actual rotational speed Ne
And the difference DN (= Ne−Nt) between the target rotation speed Nt and
The feedback correction amount DQ is obtained from the difference DN with reference to the table shown in FIG. 8, and the value of DQ and the value of Qt are added to the variable Q.

In step 8, a duty value (driving amount) Drot to be given to the rotary solenoid 21 is obtained from the value of Q with reference to a table having contents shown in FIG. 9, and is transferred to an output register in step 9. ON / OFF pulses are generated from the value of Drot and output to the rotary solenoid 21.

When the above basic injection amount (Qt) and a basic injection timing (IT) described later are matched with respect to JIS No. 2 light oil (reference fuel), a cold region such as JIS special No. 3 light oil is used. When the specified low-viscosity fuel is used until summer when the fuel temperature rises, the injection timing is substantially delayed due to a decrease in the pump efficiency of the feed pump inside the pump and an increase in the leak amount in the plunger pumping stroke. In addition, misfires frequently occur during idling, resulting in poor idling operability.

To cope with this, the control unit 35 controls the instantaneous fluctuation amplitude of the injection amount generated during the feedback control of the idle speed (or the instantaneous fluctuation of the duty value to the timing control valve generated during the feedback control of the injection timing). Fluctuation amplitude), and based on the fluctuation amplitude, determines whether or not the low-viscosity fuel is being used. If the low-viscosity fuel is being used, the basic injection timing matched with the reference fuel is determined. Correct the lead angle.

Here, FIG. 1 shows what happens when the fuel temperature is increased and a misfire occurs when the idling speed is feedback-controlled using JIS special No. 3 light oil and misfire occurs.
0 (see the lower part), the figure is a simplified model of the experimental result. As shown in the figure, at the time of misfire, the average value (Q _AV ) of the actual injection amount not only increases than when JIS No. 2 light oil is used, but also fluctuates up and down sharply at regular intervals. The misfire occurring in one cylinder produces this strongly fluctuating lump.

The fluctuation of the injection amount first swings to the increasing side as shown in the figure, but the reason for swinging to the increasing side is that as shown in FIG. 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, so the amount increases further. It seems to be in the process of being reduced. In addition,
In FIG. 11 (also for FIG. 12 and subsequent figures, which will be described later), the low-viscosity fuel is represented by light fuel.

On the other hand, when the actual injection timing is detected by the timer piston position sensor 39 in order to increase the control accuracy of the injection timing at the time of idling, and the TCV duty value is feedback-controlled so as to coincide with the target injection timing. Is superimposed on FIG. 10 (see the upper part),
In response to the fluctuation of the injection amount, the TCV duty value also
Fluctuations appear periodically at almost the same timing.

However, although the TCV duty value fluctuates first on the increasing side, it does not fluctuate on the decreasing side unlike the injection amount. This is because, in FIG. 4, the pressure in the high-pressure chamber 28 decreases due to the increase in the amount of leakage due to the decrease in fuel viscosity → the timer piston 26 moves toward the high-pressure chamber 28 (retarded side) → based on the timer piston The TCV duty value is increased so as to throttle the timing control valve 33 in order to return to the position of .fwdarw .. However, in order to follow a process in which the recovery of the pressure in the high-pressure chamber 28 is delayed due to the large amount of leakage, the TCV duty value This is because the analysis is performed solely when the vibration is increased (see FIG. 12).

The prior application (Japanese Patent Application No. 5-235215)
No.) is the J of the average value (Q _AV ) of the injection amount in FIG.
It is to judge whether the special No. 3 gas oil is used based on the increase from the use of the gas oil No. IS2 and the increase of the average value of the TCV duty value (D _AV ) from the use of the gas oil JIS No. 2. This is different from the apparatus of the present invention in that it does not pay attention to fluctuations caused by misfire.

FIG. 13 is a flowchart for explaining the fuel property judgment and the injection timing correction control 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 the engine speed Ne by referring to the table in FIG. IT [mm]
Put in. This basic injection timing (IT) matches the reference fuel.

In step 13, it is determined whether the accelerator sensor 36 is in the idle state. If the engine is in the idle state, the advance correction flag is checked in step 14, and if it is not in the set state, the advance correction of the injection timing is performed. It is determined that the operation has not been performed, and the process proceeds to step 15.

In step 15, the control sleeve position Ccs [V] is read, and the actual injection amount at idling is obtained from the value of Ccs and the engine speed Ne with reference to the map shown in FIG. This is put in the variable Q _REAL [mg / st].

In step 17, the variation amplitude of the injection amount (the variation amount of the injection amount per unit time from the average value) is determined from the value of the variable Q _REAL and the average value of the injection amount stored in the memory. ΔQ is calculated by the following equation: ΔQ = (Q _REAL −Q _AV ) / ΔT (1) where Q _{AV is} a 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,
If the injection amount during idling is increased and corrected according to the position of the selector in a vehicle with an automatic transmission, it is necessary to consider this increased amount of correction. For example,
Step 7 in FIG. 6 for various amount increase corrections during idling
Q = Qt + DQ (+ Q _V + Qa + Qtr) (2) where Q _{V is} an increase correction amount related to battery voltage Qa: An increase correction amount corresponding to an air conditioner load Qtr: An increase correction amount corresponding to a torque converter load When it is necessary to replace with the formula of (1),
The equation is changed to the following equation: ΔQ = {Q _REAL − (Q _V + Qa + Qtr) −Q _AV } / ΔT (3)

In step 18, the fluctuation amplitude ΔQ of the injection amount
Is compared with a threshold value Qth (> 0), and when ΔQ> Qth, it is determined that a low-viscosity fuel is being used.
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 the fluctuation). If misfire occurs due to a rise in fuel temperature when using a low-viscosity fuel, the fluctuation on the increasing side of the injection amount is Q
It exceeds the value of th. In addition, the 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 is a negative value), and the value of Q _REAL is smaller than this threshold value. Sometimes it can be determined that low viscosity fuel is being used. However, as shown in the lower part of FIG. 10, the fluctuation width of the fluctuation of the injection amount toward the increasing side is larger than the fluctuation width of the fluctuation toward the decreasing side, so that the determination of the fuel property on the increasing side improves the accuracy of the determination.

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

In step 20, a value obtained by adding a predetermined value ITt to the value of the variable IT is entered in the variable IT _SET , and the advance 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, the injection is performed by increasing the basic injection timing (IT) matched with the reference fuel by a predetermined value ITt. That is, the timing is advanced (see the broken line in FIG. 14). Even when a TCV duty value corresponding to the basic injection timing (IT) is given, when a low-viscosity fuel is used, the timer piston position moves to the retard side of the injection timing due to a decrease in fuel viscosity. In order to return to the original state, the injection timing is corrected to the advanced side.

According to the setting of the advance angle correction flag in step 21, the process then proceeds from step 14 to step 25 to check whether 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 the 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. I do.

When the advance correction time reaches the specified time,
It is determined that there is a possibility that the fuel has been replaced or the operating atmosphere has changed, and the process proceeds to steps 15 to 18 to check whether the fuel property has not changed. When the fuel is changed from the low-viscosity fuel to the reference fuel by the refueling after the start angle correction timer is started, the determination result in step 18 becomes ΔQ ≦ Qth because the misfire has stopped.
In this case, it is determined that the advance angle correction is not necessary, and the advance angle correction timer is stopped in step 22 to reset the contents of the timer recording. In step 23, the value of the variable IT is directly input to the variable IT _SET. Resets the lead angle correction flag.

The determination as to whether or not it is time to re-evaluate the fuel property is not limited to this. For example, it is also possible to accumulate the pump rotation speed, and determine that it is time to re-evaluate when the accumulated value exceeds a specified value. In this case, the specified value is determined based on the integrated value of the pump rotation speed until the fuel tank becomes empty (specifically, the engine is operated several times and re-evaluated about once).

On the other hand, if the vehicle is out of the idle state after setting the advance angle correction flag in step 21,
Then, the program proceeds to step 20, and if the advanced angle correction flag is set by referring to the advanced angle correction flag, the process proceeds to step 20 to continue the advance of the injection timing. In this case as well, the advance correction of the injection timing is continued so that misfire occurs 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 moving average value Q _AV of the injection amount is executed in synchronization with a reference pulse from the injection pump, for example, as shown in FIG.

[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
Perform operation to move to. These four variables are for storing the latest four actual injection amounts in the past.

In steps 33 and 34, the actual injection amount (Q
_REAL) a request, it is placed in a variable Q _n in step 35.

In step 36, the moving average value Q _{AV of the} injection amount
And calculated by the equation _{Q AV = (Q n + Q} n-1 + Q n-2 + Q n-3) / 4 ... (4), which is stored in memory at step 37. This stored value is read in step 17 of FIG.

FIG. 17 is a flowchart for performing feedback control of the injection timing.
_SET ) is executed after it is determined. FIG.
The processing of 7 is also executed by a background job or at a constant cycle (for example, 10 msec).

In step 41, the command injection timing (IT
_SET ) and a basic value of the TCV duty value with reference to a map containing FIG. 18 from the engine speed Ne,
This is put in the variable DTY [%]. The value of DTY is shown in FIG.
As shown in FIG. This is TCV
As the duty value is reduced, the timing control valve is opened, the amount of leakage from the high pressure chamber 28 to the low pressure side increases, and the timer piston position moves to the retard side. In addition, since the injection timing needs to be advanced as the rotation speed decreases, the engine speed N
e is also a parameter.

At step 42, it is determined whether or not the engine is idling. If the engine is 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 shown in FIG. The injection timing is determined, and this is entered 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 following equation: DIT = IT _REAL -IT _SET (5), and from this difference DIT, the table shown in FIG. Then, a feedback correction amount is obtained, and this is entered in a variable DDTY [mm].

At step 47, a value obtained by adding the value of DDTY to the value of DTY is entered into a variable DTY _SET representing a command TCV duty value. At step 48, the variable is transferred to an output register. 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, if it is not the time of idling, the value of the variable DTY is directly transferred to the variable DTY _SET in step 49.

Here, the operation of this example will be described. When a no-load state is detected by the accelerator sensor 36, the process shifts to idle speed feedback control, and the actual engine speed Ne becomes equal to the target engine speed _NT . The injection amount is feedback-controlled so as to 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, misfire causes the fluctuation amplitude ΔQ to exceed the threshold value Qth, so that it is determined that the use is at the time of the use of the low-viscosity fuel,
Basic injection timing (matched to 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. Even when the fuel viscosity rises significantly when the fuel temperature rises when using a low-viscosity fuel, the injection timing is not substantially retarded.

Further, whether or not the low-viscosity fuel is used is determined based on a specific phenomenon occurring at the time of misfiring (that is, instantaneous fluctuation in the injection amount). After the determination, misfire can be reliably prevented.

Further, even after the injection timing has been advanced, the advance correction is canceled after a certain period of time and the fuel properties are re-evaluated. It is possible to cope with a change in the fuel properties after the change.

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

FIG. 21 shows a second embodiment, which corresponds to FIG. The same parts as those in FIG. 13 are given the same numbers.

Only the differences from FIG. 13 will be described. In step 18, the variation amplitude .DELTA.
If it is greater than th, it is necessary to advance the injection timing. In this case, if the learned flag is set in step 51 and this flag is set, the learning value ITg of the advance correction amount has already been obtained. is determined that, the process proceeds to step _{52, iT SET = iT + ITg} ... (6) However, ITG: an expression of the advance angle correction amount learned value determining the command injection timing (iT _SET).

If the advance correction time has not reached the specified time in step 25 in FIG. 21, the learning timing timer value and the learned flag are checked in step 53, and the advance correction time (learning timer If the learning time 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 calculated.
Determine g.

Here, how the learning value ITg is determined will be described with reference to a model shown in FIG. 23. FIG. 23 shows the timing for determining the learning value ITg (that is, the process proceeds from step 53 to step 54 in FIG. 21). Timing), the injection timing is in the misfire region (screening region). In this case, first, the predetermined value ITt is given as the initial advance correction amount to return to a region where misfire does not occur, and from this state, the advance correction amount is gradually reduced (the injection timing is returned to the retard side). Then, a value obtained by adding the margin ITp to the advance 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 flowchart for determining the learning value ITg, which is executed at a constant period (10 msec).

At step 61, it is checked whether it is the first time. If it is the first time that the process has proceeded to step 61, the learning timing timer is reset at step 62, and at step 63, the variable ITc representing the advance correction amount is set to the initial advance correction. 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, step 61 to step 6
Proceeding to step 5, search for the misfire limit in steps 65 to 69, 64. That is, in steps 65 to 67, the fluctuation amplitude ΔQ of the injection amount is obtained, and in step 68, the fluctuation amplitude ΔQ and the threshold Q
Then, if ΔQ ≦ Qth, it is determined that there is still room before a misfire occurs, and the value of the variable ITc is determined in steps 69 and 64 as follows: ITc = ITc−ITr (7) where ITr: once The injection timing is gradually reduced by the formula of the amount of retard per hit, and the injection timing is retarded.

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

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

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

In this example, if the learning value ITg has been determined at least once during the previous operation using the same fuel as the currently used fuel, the injection timing corresponding to the currently used fuel immediately after the current restart. Can be given. If the learning value ITg is determined during the previous operation using the low-viscosity fuel, and the low-viscosity fuel is subsequently used during the current operation, the basic injection timing (from the timing when the engine enters the idle state after starting) The learning value ITg is added stepwise to (IT) (see FIG. 24), so that misfire can be reliably prevented even when starting with low-viscosity fuel.

FIG. 25 shows a third embodiment.
Corresponds to 3.

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

From the lighting of the warning light, it was recognized by the driver that the special air conditioner No. 3 gas oil, which is a fuel for the extremely cold season, was not suitable for driving due to the high outside air temperature (fuel temperature). By adding high light oil or replacing the fuel with light oil having high viscosity, it is possible to prevent deterioration in drivability due to misfire during idling.

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

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

Even when misfire occurs due to a rise in fuel temperature when a low-viscosity fuel is used, the fluctuation amplitude ΔQ of the injection amount may not catch on the threshold value Qth as shown in FIG. Since it is not determined that the viscous fuel is used, the drivability during idling 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 used even in the case shown in FIG.

Note that, instead of the integrated value ΔQsum, an integrated value per unit time of the actual injection amount itself can be used.

FIGS. 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,
The fuel property is determined by adding 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). As shown in FIG. 29, the fluctuation amplitude ΔQ of the injection amount
Referring to the map having the contents shown in FIG. 31 based on the fluctuation cycle and the fluctuation cycle, if the point composed of the fluctuation amplitude ΔQ and the fluctuation cycle is in the right area in FIG. 31, it is determined that the low-viscosity fuel is used (see FIG. Steps 111 and 81).

FIG. 31 shows the frequency distribution of the fluctuation amplitude and the fluctuation period of the injection amount. The position of the boundary (referred to as a standard frequency curve) separating the two regions reflects the experimental results. is there. The boundary line may be simply approximated by a straight line.

The reason why the fluctuation cycle of the injection amount changes in the multi-cylinder engine is as follows. Misfires originate from cylinders that are most likely to leak fuel. 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). Subsequently, if the fuel temperature further rises and a 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, 180 degrees crank angle
° is the fluctuation period. As described above, in the multi-cylinder engine, the fluctuation cycle changes depending on the degree of misfire.

As shown in FIG. 30, the moving average value T _AV of the fluctuation period can be used as the fluctuation period.
In FIG. 30, the maximum value of the actual injection amount is sampled into a variable Q _PEAK in steps 121 and 122, and if this exceeds a reference value in step 123, it is determined that the timing has fluctuated due to misfiring. 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, the fluctuation period (T _AV ) is further taken into consideration, so that the accuracy of determination as to whether or not the low-viscosity fuel is being used is higher than in the third embodiment of FIG. improves.

FIG. 33 shows the sixth embodiment.
Corresponding to 5.

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

The reason why the weighting coefficient b is required in the equation (9) is as follows. The rotation fluctuation amount ΔNe is small during misfire and large during normal operation, but the difference does not change significantly due to the bit. Therefore, if the weighting coefficient b is increased to expand the change of ΔNe, | ΔQ
Since the value of | / b · | ΔNe | is small during normal operation and large during misfire, the value of | ΔQ | / b · | ΔNe | is compared with a threshold value F _0, and | ΔQ | / b · | 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 enlarge the difference between the time of misfire and the time of normal.

On the other hand, | ΔQ | /
Since the value of b · | ΔNe | changes, if the injection pump is different, the threshold value F ₀ must be changed. Therefore, by introducing another weighting factor a, by changing the value of coefficient a for each injection pump, towards the threshold F ₀ it would be the same value regardless of the type of injection pump. This is why the coefficient a is required.

In this example, since the influence of the rotation fluctuation normally occurring due to the fluctuation of the engine load or the like can be eliminated, the accuracy of the fuel property judgment is improved. For example, when the injection amount fluctuates due to rotation fluctuations that can occur normally due to the idle speed feedback control, an auxiliary load is applied to the engine due to the operation of the air conditioner, the operation of the power steering when the vehicle is stopped, and the like. When the fluctuation occurs, all of the operations are normal, but in the first to fifth embodiments in which the rotation fluctuation ΔNe is not considered, it is assumed that the low viscosity fuel is also used in these cases. It cannot be said that there is no possibility of misjudgment. However, also in the first to fifth embodiments, if the variation signal of the injection amount is optimally processed and used, it is needless to say that the fuel property can be accurately determined without considering the rotation variation.

During the operation of the engine, the oil pump for power steering is always driven and rotated by the crankshaft. When the power steering is turned off when the vehicle is stopped, the oil pump for the engine is rotated when the steering angle exceeds a predetermined value. The load increases.

In the above six embodiments, the fuel property is determined based on the fluctuation amplitude ΔQ of the injection amount.
As shown in the upper part of FIG. 10, since the fuel property can be determined based on the fluctuation amplitude of the TCV duty value (drive amount), the injection amount in each of the first to sixth embodiments can be determined. Can be replaced with a part that calculates the fluctuation amplitude of the TCV duty value and determines the fuel property based on the fluctuation amplitude.

For example, FIG. 34 corresponds to FIG.
FIG. 6 shows an embodiment in which the fluctuation amplitude of the injection amount in FIG. 33 is replaced by the fluctuation amplitude of the TCV duty value.

[0123] The addition of little explanation, in FIG. 34, obtains the actual TCV duty value by referring to a table for Figure 35 with the contents of the timer piston position Ctp In step 142, put into a variable D _REAL, step 143 Then, the fluctuation amplitude ΔD of the TCV duty value is obtained by the following equation: ΔD = (D _REAL −D _AV ) / ΔT (10) where D _{AV is} a moving average value of the TCV duty value ΔT: unit time.

The variation amplitude ΔD and the threshold value D
Th is compared in step 144, and if ΔD> Dth, it is determined that a 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. If ΔD> ε3 and | ΔNe |> ε2, the TCV
The ratio F between the fluctuation amplitude of the duty value and the amount of rotation fluctuation is calculated by the following equation: F2 = c · ΔD / b · | ΔNe | (11) where c and b are weighting coefficients (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 being used (step 153 in FIG. 36).

When judging the fuel property based on the fluctuation amplitude of the TCV duty value at the time of feedback control of the injection timing at the time of idling as in the examples of FIGS. The control remains mechanical, and the present invention can be applied to a so-called partial electronic control pump in which only the injection timing is electronically controlled by a timing control valve.

Finally, the timing control valve 33 in FIG. 4 has been described with a configuration in which the smaller the TCV duty value, the larger the leakage flow rate from the high-pressure chamber 28. Conversely, the larger the TCV duty value, the more the high-pressure chamber 28 becomes. Configuration (that is, T
(The CV duty value is set to the ON time ratio of a fixed cycle.)
It can also be applied to the timing control valve. In this case, the use of special No. 3 diesel
The duty value changes to the decreasing side (FIG. 10).
In the upper stage, the upper side is the weight loss side).

[0128]

According to a first aspect of the present invention, there is provided 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 position of the control sleeve,
Means for calculating a basic injection amount matched to the reference fuel 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 Means for converting the corrected injection amount to a drive amount to be applied to the control sleeve driving actuator; 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 injection amount, means for calculating a fluctuation amplitude of the injection amount from the average value and the actual injection amount, and whether the reference fuel is used based on the fluctuation amplitude or low viscosity. Since means for determining whether fuel is used is provided, it is possible to use low-viscosity fuel. 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 determining means comprises the variation amplitude of the injection quantity and the variation cycle of the injection quantity for the two fuels, the reference fuel and the low-viscosity fuel. A memory for storing a characteristic representing a frequency distribution of points; a unit for calculating the fluctuation cycle based on the actual injection amount when calculating the fluctuation amplitude; and a point comprising the calculated fluctuation cycle and the fluctuation amplitude. Means for determining whether the frequency distribution belongs to the area of the reference fuel or the area of the low-viscosity fuel, so that the accuracy of determining whether or not the low-viscosity fuel is being used is further improved. I do.

In a third aspect based on the first aspect, the used fuel determining means calculates an engine rotation fluctuation amount when calculating the fluctuation amplitude; and a means for calculating the fluctuation amplitude and the rotation fluctuation amount. A means for calculating the 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 remove the influence of the rotation fluctuation that normally occurs due to the fluctuation of the engine load or the like from the determination as to whether it is in use.

A fourth aspect of the present invention is a distribution type injection pump in which the amount of fuel leaked from the high pressure chamber at one end of the timer piston and leaked to the low pressure side is adjusted by a drive amount given to the timing control valve, and the position of the timer piston is adjusted. , A means for calculating a basic injection timing matched to a reference fuel according to the engine speed, a means for calculating an actual injection timing from a detection value of the timer piston position sensor, and Means for feedback correcting the drive amount given 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 during idling. Calculate the actual drive amount given to the control valve 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. Means to determine whether fuel is low or low-viscosity fuel is being used, so it is important to determine not only when low-viscosity fuel is being used, but also that misfire has occurred due to an increase in fuel temperature. In addition to the need for an additional sensor, the control of the fuel injection amount remains mechanical due to cost constraints, and the injection pump is only electronically controlled by the timing control valve. Can be applied.

In a fifth aspect based on the fourth aspect, the used fuel judging means comprises the fluctuation amplitude of the driving amount and the fluctuation period of the driving amount for the two fuels, the reference fuel and the low-viscosity fuel. A memory for storing a characteristic representing a frequency distribution of points; a unit for calculating the fluctuation cycle based on the actual drive amount when calculating the fluctuation amplitude; and a point comprising the calculated fluctuation cycle and the fluctuation amplitude. Means for determining whether the frequency distribution belongs to the area of the reference fuel or the area of the low-viscosity fuel, so that the accuracy of determining whether or not the low-viscosity fuel is being used is further improved. I do.

In a sixth aspect based on the fourth aspect, the used fuel determining means calculates means for calculating the engine rotation fluctuation when calculating the fluctuation amplitude; and a means for calculating the fluctuation amplitude and the rotation fluctuation amount. A means for calculating the 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. From the determination of whether or not the fuel cell is in use, it is possible to eliminate the influence of the rotation fluctuation that normally occurs due to the fluctuation of the engine load and the like, and the accuracy of the fuel property determination is improved.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, a means for issuing a warning when the used fuel determining means determines that the low viscosity fuel is being used. Since this warning, we recognize that the fuel currently used is not suitable for driving from this warning, add a reference fuel that is a fuel with higher viscosity than the current fuel, or replace the fuel with the reference fuel, Deterioration of drivability due to misfire during idling can be prevented.

According to an eighth aspect of the present invention, the position of the control sleeve is adjusted in accordance with the drive amount given to the actuator for driving the control sleeve, and the flow rate of fuel leaked from the high pressure chamber at one end of the timer piston to the low pressure side is controlled. A distribution type injection pump adjusted by a drive amount given to a control valve, a means for calculating a basic injection timing matched with a reference fuel according to an engine speed, and a sensor for detecting the control sleeve position, Means for calculating a basic injection amount matched to the reference fuel 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 Injection amount to be used to drive the control sleeve Means for converting to a drive amount given to the 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. Means for calculating a fluctuation amplitude of the injection amount from the average value and the actual injection amount, and determining whether the reference fuel or the low-viscosity fuel is used based on the fluctuation amplitude. Means for calculating a value obtained by advancing the basic injection timing when using low-viscosity fuel from the determination result as a command injection timing, and calculating the basic injection timing as it is as a command injection timing when using a reference fuel; Means for converting the command injection timing into a drive amount given to the timing control valve. Even when the fuel temperature increases, it is possible to reliably prevent a misfire during idling.

According to a ninth aspect of the present invention, there is provided a distribution type injection pump in which a flow rate of fuel leaked from a high pressure chamber at one end of a timer piston to a low pressure side is adjusted by a drive amount given to a timing control valve. , A means for calculating a basic injection timing matched to a reference fuel according to the engine speed, a means for calculating an actual injection timing from a detection value of the timer piston position sensor, and 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 based on the detection value of the timer piston position sensor during the feedback correction of the injection timing during idling. Calculate the actual drive amount given to the valve A step, means for calculating an average value from the actual drive amount, means for calculating a fluctuation amplitude of the drive amount from the average value and the actual drive amount, and the reference fuel is used based on the fluctuation amplitude. Means for determining whether or not the low-viscosity fuel is used, and based on the result of the determination, when the low-viscosity fuel is used, a value obtained by advancing the basic injection timing is used as the command injection timing, and the reference fuel is used. In some cases, means for calculating the basic injection timing as it is as the command injection timing is provided, so that misfire during idling can be reliably prevented even when using low-viscosity fuel and increasing the fuel temperature.

According to a tenth aspect of the present invention, the position of the control sleeve is adjusted in accordance with the amount of drive given to the actuator for driving the control sleeve, and the flow rate of fuel leaked from the high pressure chamber at one end of the timer piston to the low pressure side is adjusted. A distribution-type injection pump adjusted by a drive amount applied to a control valve, a unit for calculating a basic injection timing matched with a reference fuel according to the engine speed, and a learning value of an advance correction amount of the injection timing 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 basic injection amount matched with a reference fuel according to the engine speed and load. Means to calculate the idle speed and the target speed during idling. Means for feedback-correcting the injection amount so as to perform the operation, means for converting the injection amount to be feedback-corrected into a drive amount to be applied to the control sleeve driving actuator, and means for controlling the control sleeve position sensor during the feedback correction of the idle rotation. Means for calculating the actual injection amount from the detected value, means for calculating the average value from the actual injection amount, means for calculating the fluctuation amplitude of the injection amount from the average value and the actual injection amount, A means for determining whether the reference fuel is used or a low-viscosity fuel is used based on the result of the determination, and when the low-viscosity fuel is used, the basic injection timing is advanced by the learning value based on the determination result. Value as the command injection timing, and when using the reference fuel, the basic injection timing as the command injection timing as it is. 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,
Means for determining a value obtained by adding a margin to the advance correction amount at the found misfire timing as the learning value is provided, so that the learning value is determined during the previous operation using the low-viscosity fuel, If it is assumed that low-viscosity fuel will also be used during this operation, the learning value will be added stepwise to the basic injection timing from the time when the engine enters the idle state after starting, and starting with low-viscosity fuel will start. When it does, misfire can be reliably prevented.

The eleventh invention is directed to a distribution type injection pump in which the flow rate of fuel leaked to the low pressure side by bypassing from the high pressure chamber at one end of the timer piston is adjusted by a drive amount given to the timing control valve, , A means for calculating the basic injection timing matched to the reference fuel according to the engine speed, a memory for storing a learning value of the advance correction amount of the injection timing, and a value for the memory. Means for backing up even after the engine is stopped, means for calculating the actual injection timing from the detection value of the timer piston position sensor, and drive for giving to the timing control valve such that the actual injection timing coincides with the command injection timing at idle. means for feeding back the amount correction, the feedback of the injection timing at the time of idle Means for calculating an actual drive amount to be given to the timing control valve from the detection value of the timer piston position sensor during the correction, means for calculating an average value from the actual drive amount, and a method for calculating the average value and the actual injection amount. Means for calculating the fluctuation amplitude of the drive amount; means for determining whether the reference fuel is used or low-viscosity fuel based on the fluctuation amplitude; and Means for calculating the command injection timing using a value obtained by advancing the basic injection timing with the learning value when used, and calculating the basic injection timing as it is when using the reference fuel;
Means for searching for an advance correction amount at a misfire timing based on the fluctuation amplitude, and means for determining a value obtained by adding a margin to the advanced angle correction amount at the found misfire timing as the learning value are provided. Therefore, if the learning value is determined during the previous operation using the low-viscosity fuel and the low-viscosity fuel is also used during the current operation, the basic injection is started from the timing when the engine enters the idle state after starting. The learning value is added in a stepwise manner at the time, and even when starting with low-viscosity fuel, misfire can be reliably prevented.

According to a twelfth aspect of the present invention, in any one of the eighth to eleventh aspects, the advance correction is canceled after a lapse of a predetermined time after the injection timing is advanced. Then, the fuel property is re-evaluated, so that it is possible to cope with a change in the fuel property after the injection timing is advanced.

[Brief description of the drawings]

FIG. 1 is a longitudinal 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 part.

FIG. 5 is a control system diagram of the electronic control 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 a feedback correction amount DQ of an injection amount.

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

FIG. 10 is a waveform diagram showing, in a simplified model, each variation of an injection amount and a TCV duty value generated at the time of misfire.

FIG. 11 is a flowchart for explaining why an increase in the injection amount occurs at the time of misfire.

FIG. 12 is a flowchart for explaining why the TCV duty value fluctuates on the increasing side at the time of misfire.

FIG. 13 is a flowchart illustrating a fuel property determination and an 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 an injection amount.

FIG. 17 is a flowchart for performing feedback control of the injection timing.

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

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

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

FIG. 21 is a flowchart illustrating a fuel property determination and a fuel injection timing correction control using the determination result according to the second embodiment.

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

FIG. 23 is a waveform chart for explaining determination of a learning value ITg in the second embodiment.

FIG. 24 is a diagram showing a case where the learning value ITg is determined during the previous operation using the low-viscosity fuel and the low-viscosity fuel is subsequently used during the current operation. FIG. 9 is a waveform diagram for explaining how a learning value ITg is added.

FIG. 25 is a flowchart illustrating a fuel property determination and a warning using the determination result according to the third embodiment.

FIG. 26 is a flowchart for explaining a fuel property determination and a warning using the determination result of the fourth embodiment.

FIG. 27 is a flowchart for explaining the calculation of the integrated value ΔQsum of the fluctuation amplitude in the fourth embodiment.

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

FIG. 29 is a flowchart illustrating a determination of fuel properties and a warning using the determination result in the fifth embodiment.

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

FIG. 31 is a characteristic diagram illustrating a frequency distribution of a fluctuation amplitude and a fluctuation cycle of an injection amount according to a fifth embodiment.

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

FIG. 33 is a flowchart for explaining a fuel property determination and a warning using the determination result of the sixth embodiment.

FIG. 34 is a flowchart for explaining a fuel property determination and a warning using the determination result of the seventh embodiment.

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

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

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

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

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

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

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

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

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

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

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

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

[Explanation of symbols]

16 Control Sleeve 21 Rotary Solenoid (Control Sleeve Driving Actuator) 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 Driving Actuator 53 Timing Control Valve 54 Control Sleeve Position Sensor 55 Basic injection amount calculation means 56 Idle rotation feedback correction means 57 Driving 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 Change period calculation means 73 Area Determination means 81 Rotation fluctuation amount calculation means 82 Ratio calculation means 83 Comparison means 9 Timer piston position sensor 92 Basic injection timing calculating means 93 Actual injection timing calculating means 94 Driving amount feedback correcting means 96 Actual driving amount calculating means 97 Average value calculating means 98 Fluctuation amplitude calculating means 99 Used fuel determining means 101 Frequency distribution memory 102 Fluctuation cycle Calculation means 103 Area determination means 111 Ratio calculation means 112 Comparison means 121 Command injection timing calculation means 122 Driving amount conversion means 131 Driving 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

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 45/00 364 F02D 41/40

Claims (12)

(57) [Claims] 1. A distribution type injection pump in which a control sleeve position is adjusted according to a drive amount given to a control sleeve driving actuator, a sensor for detecting the control sleeve position, and a basic injection matched to 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 Means for converting to a drive amount to be 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; means for calculating an average value from the actual injection amount From this average value and the actual injection amount, A diesel engine comprising: means for calculating a fluctuation amplitude of an injection amount; and means for determining whether the reference fuel or the low-viscosity fuel is used based on the fluctuation amplitude. Engine fuel property detector. 2. The fuel consumption determining means stores a characteristic representing a frequency distribution of points consisting of the fluctuation amplitude of the injection amount and the fluctuation period of the injection amount for the two fuels of the reference fuel and the low-viscosity fuel. A memory for calculating the fluctuation amplitude based on the actual injection amount when calculating the fluctuation amplitude; and a point comprising the calculated fluctuation period and the fluctuation amplitude is a point of the reference fuel on the frequency distribution. The fuel property detecting device for a diesel engine according to claim 1, further comprising means for determining whether the fuel property belongs to the area or the low viscosity fuel area. 3. The fuel consumption determining means calculates an engine rotation fluctuation amount when calculating the fluctuation amplitude;
Means for calculating the ratio between the fluctuation amplitude and the rotation fluctuation amount,
The diesel engine according to claim 1, further comprising means for comparing the ratio with a threshold value to determine whether the reference fuel is used or the low-viscosity fuel is used. Fuel property detector. 4. A distribution type injection pump in which a flow rate of fuel leaked to a low pressure side from a high pressure chamber at one end of a timer piston is adjusted by a driving amount given to a timing control valve, and a sensor for detecting a position of the timer piston. Means for calculating a basic injection timing matched to a reference fuel according to the engine speed; means for calculating an actual injection timing from a value detected by the timer piston position sensor; and Means for feedback correcting the drive amount given to the timing control valve so as to coincide with the basic injection timing; and providing the timing control valve with the detected value of the timer piston position sensor during the feedback correction of the injection timing at idle. Means for calculating the actual driving 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. Means for determining whether low-viscosity fuel is being used. A fuel property detection device for a diesel engine, comprising: 5. A method according to claim 1, wherein the used fuel determining means stores a characteristic representing a frequency distribution of points including the fluctuation amplitude of the driving amount and a fluctuation period of the driving amount for the two fuels of the reference fuel and the low-viscosity fuel. A memory for calculating the fluctuation amplitude based on the actual drive amount when calculating the fluctuation amplitude; and a point comprising the calculated fluctuation period and the fluctuation amplitude is a point 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 the fuel property belongs to the area or the low viscosity fuel area. 6. The used fuel determining means calculates an engine rotation fluctuation amount when calculating the fluctuation amplitude;
Means for calculating the ratio between the fluctuation amplitude and the rotation fluctuation amount,
5. The diesel engine according to claim 4, further comprising means for comparing the ratio with a threshold to determine whether the reference fuel is used or the low-viscosity fuel is used. Fuel property detector. 7. The apparatus according to claim 1, further comprising a warning unit provided when the used fuel determining unit determines that the low-viscosity fuel is being used. 3. The fuel property detection device for a diesel engine according to item 1. 8. A control sleeve position is adjusted in accordance with a drive amount given to a control sleeve drive actuator, and a flow rate of fuel leaked from a high pressure chamber at one end of a timer piston to a low pressure side is given to a timing control valve. A distribution-type injection pump adjusted by a driving amount; a means for calculating a basic injection timing matched with a reference fuel according to the engine speed; a sensor for detecting the control sleeve position; Means for calculating the matched basic injection 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 control sleeve drive actuator Means for converting the actual injection amount from the detected value of the control sleeve position sensor during the 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 means for determining whether the reference fuel or the low-viscosity fuel is used based on the fluctuation amplitude. Means for calculating a value obtained by advancing the basic injection timing when the low-viscosity fuel is used from the determination result as the command injection timing, and calculating the basic injection timing as it is as the command injection timing when using the reference fuel; 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 a flow rate of fuel leaked to a low pressure side from a high pressure chamber at one end of a timer piston is adjusted by a drive amount given to a timing control valve, and a sensor for detecting a position of the timer piston. Means for calculating a basic injection timing matched to a reference fuel according to the engine speed; means for calculating an actual injection timing from a value detected by the timer piston position sensor; and Means for feedback-correcting the drive amount given to the timing control valve so as to coincide with the commanded injection timing; and an actual value given to the timing control valve from the detection value of the timer piston position sensor during the feedback correction of the injection timing during idling Means for calculating the driving amount; Means for calculating an average value from the actual driving amount; means for calculating the fluctuation amplitude of the driving amount from the average value and the actual driving amount; and whether or not the reference fuel is used based on the fluctuation amplitude. Means for determining whether a viscous fuel is being used; and, based on the determination result, a value obtained by advancing the basic injection timing when using a low-viscosity fuel as the command injection timing, and when using a reference fuel, the basic injection Means for calculating a timing as it is as the command injection timing. An injection timing control device for a diesel engine. 10. A control sleeve position is adjusted according to a drive amount given to a control sleeve drive actuator, and a flow rate of fuel leaked from a high pressure chamber at one end of a timer piston to a low pressure side is given to a timing control valve. A distribution-type injection pump that is adjusted by a drive amount, a unit that calculates a basic injection timing that matches a reference fuel according to the engine speed, and a memory that stores a learning value of an advance correction amount of the injection timing. Means for backing up the value of the memory even after the engine is stopped; a sensor for detecting the position of the control sleeve; and means for calculating a basic injection amount matched with a reference fuel according to the engine speed and load. So that the idling speed matches the target speed during idling. Means for feedback-correcting the injection amount; means for converting the feedback-corrected injection amount to a drive amount to be applied to the control sleeve driving actuator; and a detection value of the control sleeve position sensor during the idle rotation feedback correction. A means for calculating an actual injection amount; a means for calculating an average value from the actual injection amount; a means for calculating a fluctuation amplitude of the injection amount from the average value and the actual injection amount; Means for determining whether reference fuel or low-viscosity fuel is used; and, based on the determination result, when using low-viscosity fuel, instruct a value obtained by advancing the basic injection timing by the learning value with the learning value. When the reference fuel is used, the basic injection timing is calculated as it is as the command injection timing. A means for converting the command injection timing into a drive amount given to the timing control valve; a means for searching for an advance correction amount at a misfire timing based on the fluctuation amplitude; Means for determining, as the learning value, a value obtained by adding a margin to the advance angle correction amount, the injection timing control device for a diesel engine. 11. A distribution type injection pump in which a flow rate of fuel leaked to a low pressure side by bypassing from a high pressure chamber at one end of a timer piston is adjusted by a driving amount given to a timing control valve, and a sensor for detecting a position of the timer piston. Means for calculating a basic injection timing matched with the reference fuel according to the engine speed; a memory for storing a learning value of the advance correction amount of the injection timing; and a value for the memory after stopping the engine. Means for calculating the actual injection timing from the detection value of the timer piston position sensor; and feedback correction of the drive amount given to the timing control valve so that the actual injection timing matches the command injection timing at the time of idling. means for, in said feedback correction of injection timing at the time of idle Means for calculating an actual drive amount given to the timing control valve from the detection value of the timer piston position sensor; means for calculating an average value from the actual drive amount; and a drive amount based on the average value and the actual injection amount. Means for calculating a fluctuation amplitude; means for determining whether the reference fuel is used or low-viscosity fuel is used based on the fluctuation amplitude; and Means for calculating a value obtained by advancing the basic injection timing by the learning value as the command injection timing, and calculating the basic injection timing as the command injection timing as it is when using the reference fuel; and a misfire timing based on the fluctuation amplitude. Means for searching for an advance correction amount at the time of misfire, and a value obtained by adding a margin to the amount of advance correction at the found misfire timing. Injection timing control device for a diesel engine, characterized in that a means for determining the value. 12. The fuel injection device according to claim 8, wherein the advance correction is canceled and the fuel property is re-evaluated after a predetermined time has elapsed even after the injection timing has been advanced.
The injection timing control device for a diesel engine according to any one of the above.