JPH05222995A - Fuel injection amount control device for diesel engine - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the change in the rotation speed is large, the fuel injection amount control is performed by determining the target injection amount that matches the rotation speed when the fuel injection is actually performed. [Structure] The number of pulses from a certain reference position of an engine rotation pulse to a target crank angle corresponding to a target injection amount and a surplus angle less than one pulse are obtained. In predicting the angular time used for time conversion of the surplus angle, the time TN13 in the same combustion cycle,
TN6 is obtained, and the difference between both times TN13 and TN6 is taken as the time difference ΔTN corresponding to the change in rotation speed. Then, based on the time difference ΔTN, the previous angular time TS1125 (i-
Correct 1). At the same time, the reference rotation speed NE1 is used to obtain the calculation rotation speed for calculating the target injection amount.
(I) is corrected based on the time difference ΔTN. Therefore, the target injection amount is determined based on the corrected rotational speed for calculation that predicts the rotational speed change in the current combustion cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine applied to, for example, an automobile, and more specifically, a fuel injection amount control device for controlling a fuel injection amount by obtaining a target injection amount on the basis of its rotational speed or the like. It is about.

[0002]

2. Description of the Related Art Conventionally, for example, in a fuel injection pump of an electronically controlled diesel engine, an electromagnetic spill valve or the like is controlled so that the fuel injection amount obtained according to the lift of the plunger reaches a required target injection amount. The spill port is open. As a result, the fuel from the high pressure chamber of the plunger overflows (spills) to the fuel chamber, and the end of the pressure feed of the fuel, that is, the end timing of the fuel injection is controlled to obtain the required target injection amount.

In the control of such an electromagnetic spill valve, a target spill angle is usually based on a signal which is synchronized with the lift of the plunger and is input at a constant pump rotation angle, for example, an engine rotation pulse and an average rotation speed of the engine. Was converted into time, and the target spill time was decided accordingly. Then, the electromagnetic spill valve was controlled to be turned on and off based on the target spill time.

For example, in the technology disclosed in Automobile Technology Case Collection No. 7, issue number: 92140 (issued on Jan. 20, 1992, edited by Japan Automobile Manufacturers Association, Patent Subcommittee), a certain target injection amount is obtained in order to obtain a required injection amount. Based on the engine rotation pulse obtained for each crank angle, a pulse count number from a certain reference position of the engine rotation pulse to a target spill angle and a surplus angle less than one pulse were obtained.
Then, the surplus angle is converted into time based on the rotation speed of the engine, so that the target spill timing is determined. In this case, as shown in FIG. 14, the engine rotation time (spill time pulse time) detected between the predetermined crank angles including the target spill angle in the previous combustion cycle.
TS1125 (i-1) was corrected based on the average rotation speed of the engine to predict the spill pulse time in the present combustion cycle. And
The surplus angle of this time was converted into time based on the predicted spill time pulse time. Here, as the above-mentioned average rotation speed, the average rotation speed at the time of rotation increase and the average rotation speed at the time of rotation decrease in the same combustion cycle were used. Then, the rotation increase time TN1 required to rotate by a constant crank angle near each of the average rotation speed positions.
3 (i) and time TN6 (i) at the time of rotation decrease are obtained,
Based on the difference between the two times TN13 (i) and TN6 (i), the previous spill pulse time TS1125 (i-
1) was being corrected.

With this configuration, even when the engine speed changes, the surplus angle is converted into time with accuracy, and the end timing of fuel injection is controlled with accuracy to obtain the required target injection amount accurately. ..

[0006]

However, in the above-mentioned conventional technique, the required target injection amount itself is determined based on the latest rotation speed at the time of the calculation. Therefore, the target injection amount may be a value adapted to a rotational speed different from the rotational speed at which fuel injection is actually performed, and there is a possibility that the fuel injection amount adapted to the operating state may not be obtained. It was In particular, when the rotation speed changes abruptly, the rotation speed at the time when fuel injection is actually performed is not used, so the calculation of the target injection amount becomes incorrect, and the diesel engine does There was a risk of surge.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to make a target injection suitable for the rotational speed at which fuel injection is actually performed, even if the rotational speed of the diesel engine greatly changes. It is an object of the present invention to provide a fuel injection amount control device for a diesel engine capable of determining the amount and controlling the fuel injection amount.

[0008]

In order to achieve the above object, in the present invention, as shown in FIG. 1, in a high pressure chamber M3, a plunger M2 is reciprocally driven in conjunction with the rotation of a diesel engine M1. Fuel injection pump M for sending pressurized fuel to diesel engine M1 for injection
4 and an overflow adjustment valve that is opened to end the pressurization of fuel in the high pressure chamber M3 to adjust the amount of fuel injected from the fuel injection pump M4 and adjusts the overflow of fuel from the high pressure chamber M3. M5 and overflow timing calculation means M6 for calculating a target overflow timing corresponding to the injection end timing in order to obtain the target injection amount determined according to the operating state of the diesel engine M1.
And an engine rotation detecting means M7 for detecting an engine rotation pulse for each constant crank angle of the diesel engine M1 and detecting an instantaneous rotation speed for each engine rotation pulse, and sequentially detected by the engine rotation detecting means M7. Based on the engine rotation pulse, the count number of the engine rotation pulse from a certain reference position of the engine rotation pulse to the target overflow timing calculated by the overflow timing calculation means M6 and a surplus angle less than the one pulse are calculated. Based on the engine rotation pulse detected by the surplus angle calculation means M8 and the engine rotation detection means M7, a constant crank angle is provided in the vicinity of the average rotation speed position when the rotation speed of the diesel engine M1 is increased and when the rotation speed is decreased in the same combustion cycle. Each crank angle time required to rotate An average rotational speed position / time calculating means M9 for calculating, and a rotation calculating a rotational speed change at that time based on the crank angle times at the time of rotation increase and at the time of rotation decrease calculated by the average rotational speed position / time calculation means M9. The target overflow calculated by the overflow timing calculation means M6 based on the speed change calculation means M10, the engine rotation pulse detected by the engine rotation detection means M7, and the rotation speed change calculated by the rotation speed change calculation means M10. A pulse time calculating means M11 for predicting and calculating the required time for one pulse corresponding to the time, and a surplus angle calculating means M8.
The remainder angle calculated by the pulse time calculation means M1
Angle time conversion means M12 for converting time based on the required time for one pulse predicted and calculated by 1 and high pressure chamber M3
Angle calculation means M8 for executing the overflow of fuel from the
The overflow adjustment valve M5 is opened at a timing determined by the engine rotation pulse count up to the target overflow timing calculated by the above and the time conversion value of the surplus angle by the angle time conversion means M12. Means M13
In the fuel injection amount control device for a diesel engine, the instantaneous rotation speed of each diesel engine M1 at a predetermined crank angle position within the same combustion cycle is determined based on the instantaneous rotation speed of each engine rotation pulse detected by the engine rotation detection means M7. A rotation speed calculation means M14 for calculating the rotation speed as a rotation speed for calculation used to calculate the target injection amount, and a rotation speed calculation means M1 for the calculation.
4 for correcting the calculation rotational speed calculated based on the change in the rotational speed calculated by the rotational speed change calculating means M10, and the arithmetic rotational speed correction means M15 for correcting the calculated rotational speed. Target injection amount calculation means M16 for calculating and determining the target injection amount based on the corrected calculation rotational speed and the like.

[0009]

According to the above structure, as shown in FIG. 1, the plunger M2 is reciprocally driven in conjunction with the rotation of the diesel engine M1, so that the fuel pressurized in the high pressure chamber M3 is supplied to the diesel engine M1. Is pumped to and jetted. At this time, by opening the overflow adjustment valve M5,
The fuel overflows from the high pressure chamber M3, the pressurization of fuel in the high pressure chamber M3 is completed, and the fuel injection amount from the fuel injection pump M4 is adjusted.

Then, in order to obtain the target injection amount determined according to the operating state of the diesel engine M1, the overflow timing calculating means M6 calculates the target overflow timing corresponding to the injection end timing of the target injection amount. .. Further, the engine rotation detecting means M7 detects an engine rotation pulse for each constant crank angle of the diesel engine M1, and also detects an instantaneous rotation speed for each engine rotation pulse.
Further, based on the engine rotation pulses detected in sequence, the remainder angle calculation means M8 causes the engine rotation pulse count number from the reference position of the engine rotation pulse to the target overflow timing to be less than the one pulse count. The angle is calculated. Further, the calculated remainder angle is converted into time by the angle time conversion means M12 based on the required time for one pulse. The overflow adjustment executing means M13
The time timing is determined from the count number of the engine rotation pulse up to the target overflow timing and the time conversion value of the surplus angle, and the overflow adjustment valve M is based on the time timing.
5 is opened and the overflow of fuel from the high pressure chamber M3 is executed.

Here, the average rotational speed position time calculation means M
9, the crank angle time required to rotate by a constant crank angle is calculated in the vicinity of the average rotation speed position when the rotation speed is increased and when the rotation speed is decreased in the same combustion cycle of the diesel engine M1. To be done. Further, based on the calculated both crank angle times, the rotational speed change calculation means M10
The change in rotation speed at that time is calculated. Further, the pulse time calculating means M11 predictively calculates the required time for one pulse corresponding to the target overflow timing based on the calculated rotation speed change and the engine rotation pulse.

Therefore, the required time for one pulse corresponding to the change in the rotation speed of the diesel engine M1 is predicted and calculated, and the calculated required time is calculated as the angle time conversion means M1.
2 used for time conversion of surplus angle. Therefore, the determination of the time timing in the overflow adjustment execution means M13 is made more appropriate according to the change in the rotation speed.

In addition, the calculation rotational speed calculating means M14 calculates the target injection amount by the instantaneous rotational speed at the predetermined crank angle position within the same combustion cycle, based on the instantaneous rotational speed for each engine rotation pulse. It is calculated as the rotation speed for calculation to be used. Further, the calculated rotation speed for calculation is corrected by the calculation rotation speed correction means M15 based on the change in rotation speed. Further, based on the corrected calculation rotational speed and the like, the target injection amount calculation means M
By 16, the target injection amount used in the overflow timing calculation means M6 is calculated and determined.

Therefore, the target injection amount is determined based on the rotation speed that predicts the rotation speed change in the current combustion cycle, and the target overflow timing is determined by reflecting the rotation speed change. Therefore, when the fuel injection is actually performed, the fuel injection amount suitable for the rotation speed change can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a fuel injection amount control device for a diesel engine according to the present invention is embodied in an automobile will be described below in detail with reference to FIGS.

FIG. 2 is a schematic configuration diagram showing a fuel injection amount control device for a diesel engine with a supercharger in this embodiment, and FIG. 3 is a sectional view showing the distribution type fuel injection pump 1. The fuel injection pump 1 includes a drive pulley 3 drivingly connected to a crankshaft 40 of a diesel engine 2 via a belt or the like. Then, the rotation of the drive pulley 3 drives the fuel injection pump 1, and the fuel is pumped to the fuel injection nozzles 4 provided for each cylinder (four cylinders in this case) of the diesel engine 2 to perform fuel injection. Be seen.

In the fuel injection pump 1, the drive pulley 3 is attached to the tip of the drive shaft 5.
Further, a fuel feed pump (developed by 90 degrees in this figure) 6 which is a vane type pump is provided in the middle of the drive shaft 5. Further, a disc-shaped pulsar 7 is attached to the base end side of the drive shaft 5. The diesel engine 2 is attached to the outer peripheral surface of the pulsar 7.
The same number as the number of cylinders, that is, four cutting teeth (eight in this case) are formed at equal angular intervals, and 14 projections (56 in total) are formed between the cutting teeth at equal angles. It is formed at intervals. The base end of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown).

A roller ring 9 is provided between the pulsar 7 and the cam plate 8, and a plurality of cam rollers 10 are mounted along the circumference of the roller ring 9 so as to face the cam face 8a of the cam plate 8. There is. Cam face 8
The number a is provided in the same number as the number of cylinders of the diesel engine 2. The cam plate 8 is constantly urged and engaged with the cam roller 10 by the spring 11.

A base end of a fuel pressurizing plunger 12 is integrally rotatably attached to the cam plate 8, and the cam plate 8 and the plunger 12 are rotated in association with the rotation of the drive shaft 5. That is, when the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via a coupling (not shown), the cam plate 8 is engaged with the cam roller 10 while rotating, and the same number as the number of cylinders in the left-right direction in the drawing is obtained. Is driven back and forth. In addition, the plunger 12 is reciprocally driven in the same direction while rotating with the reciprocating drive. That is, the plunger 12 is moved forward (lifted) while the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, and vice versa.
2 is reactivated.

The plunger 12 is fitted into a cylinder 14 formed in the pump housing 13, and a high pressure chamber 15 is provided between the tip end surface of the plunger 12 and the bottom surface of the cylinder 14.
Has become. Also, on the outer periphery of the tip end side of the plunger 12,
The same number of intake grooves 16 and distribution ports 17 as the number of cylinders of the diesel engine 2 are formed. Also, those suction grooves 16
And the pump housing 13 corresponding to the distribution port 17.
A distribution passage 18 and a suction port 19 are formed therein.

Then, the drive shaft 5 is rotated to drive the fuel feed pump 6, whereby fuel is supplied from a fuel tank (not shown) into the fuel chamber 21 through the fuel supply port 20. Further, during the suction stroke in which the plunger 12 is returned and the high pressure chamber 15 is depressurized, the suction groove 1
The fuel is introduced from the fuel chamber 21 into the high-pressure chamber 15 by communicating one of the six with the suction port 19. On the other hand, during the compression stroke in which the plunger 12 is moved forward and the high-pressure chamber 15 is pressurized, fuel is pressure-fed and injected from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder.

A spill passage 22 for fuel overflow (spill) is formed in the pump housing 13 to connect the high pressure chamber 15 and the fuel chamber 21. An electromagnetic spill valve 23 as a spill adjusting valve for adjusting the fuel spill from the high pressure chamber 15 is provided in the middle of the spill passage 22. The electromagnetic spill valve 23 is a normally open type valve, and the valve body 25 is opened to spill the fuel in the high pressure chamber 15 to the fuel chamber 21 when the coil 24 is not energized (OFF). When the coil 24 is energized (turned on), the valve body 25 is closed and the spill of fuel from the high pressure chamber 15 to the fuel chamber 21 is stopped.

Therefore, by controlling the energization time of the electromagnetic spill valve 23, the valve 23 is closed / opened and the spill of fuel from the high pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel inside the high pressure chamber 15 is depressurized and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even if the plunger 12 moves forward, the fuel pressure in the high-pressure chamber 15 does not rise while the electromagnetic spill valve 23 is open, and fuel injection from the fuel injection nozzle 4 is not performed. In addition, by controlling the closing / opening timing of the electromagnetic spill valve 23 during the forward movement of the plunger 12, the injection end from the fuel injection nozzle 4 is adjusted and the fuel injection amount is controlled.

Below the pump housing 13, there is provided a timer device (which is expanded 90 degrees in this figure) 26 for controlling the fuel injection timing. The timer device 26 changes the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5 to change the timing at which the cam face 8a engages with the cam roller 10, that is, the reciprocating drive timing of the cam plate 8 and the plunger 12. It is for.

The timer device 26 is driven by control hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the housing 27, and a timer in a low pressure chamber 29 on one side of the timer housing 27. It is composed of a timer spring 31 and the like for urging the piston 28 against the pressurizing chamber 30 on the other side. The timer piston 28 is connected to the roller ring 9 via the slide pin 32.

In the pressure chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. Then, the position of the timer piston 28 (hereinafter referred to as "timer piston position") is determined by the equilibrium relationship between the fuel pressure and the urging force of the timer spring 31. Further, by determining the timer piston position, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 via the cam plate 8 is determined.

The timer device 26 is provided with a timer control valve (TCV) 33 in order to adjust the fuel pressure acting as the control oil pressure of the timer device 26. That is, the pressurizing chamber 30 and the low pressure chamber 29 of the timer housing 27 are connected to each other by the communication passage 3
4 are connected to each other, and TC is provided in the middle of the communication passage 34.
V33 is provided. The TCV 33 is an electromagnetic valve that is opened / closed by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by the opening / closing control of the TCV 33. Then, by adjusting the fuel pressure, the lift timing of the plunger 12 is controlled, and the fuel injection timing from each fuel injection nozzle 4 is controlled.

On the upper part of the roller ring 9, a rotation speed sensor 35 as an engine rotation detecting means composed of an electromagnetic pickup coil is attached so as to face the outer peripheral surface of the pulsar 7. The rotation speed sensor 35 detects the passage of the protrusions of the pulsar 7 when the protrusions of the pulsar 7 cross each other, and outputs a timing signal corresponding to the engine rotation speed NE, that is, an engine rotation pulse for each constant crank angle (11.25 ° CA). Is output. Further, the rotation speed sensor 35 detects an instantaneous rotation speed for each engine rotation pulse. Further, since this rotation speed sensor 35 is integrated with the roller ring 9, it outputs a reference timing signal to the plunger lift at a constant timing regardless of the control operation of the timer device 26.

Next, the diesel engine 2 will be described. In the diesel engine 2, a main combustion chamber 44 corresponding to each cylinder is formed by the cylinder 41, the piston 42, and the cylinder head 43. or,
A sub combustion chamber 45 communicating with each of the main combustion chambers 44 is provided for each cylinder. And each auxiliary combustion chamber 45
The fuel injected from each fuel injection nozzle 4 is supplied to. A well-known glow plug 46 as a start-up assist device is attached to each sub-combustion chamber 45.

The diesel engine 2 is provided with an intake pipe 47 and an exhaust pipe 48, respectively. Further, the intake pipe 47 is provided with a compressor 50 of a turbocharger 49 that constitutes a supercharger, and the exhaust pipe 48 is provided with a turbine 51 of the turbocharger 49. Further, the exhaust pipe 48 is provided with a waste gate valve 52 for adjusting the supercharging pressure PiM. As is well known, the turbocharger 49 uses the energy of exhaust gas to rotate the turbine 51, and rotates the compressor 50 coaxially with the turbine 51 to pressurize intake air. Due to this action, a high-density air-fuel mixture is sent to the main combustion chamber 44 to burn a large amount of fuel, and the output of the diesel engine 2 is increased.

The diesel engine 2 has an exhaust pipe 4
A recirculation pipe 54 is provided for recirculating a part of the exhaust gas in 8 to the intake port 53 of the intake pipe 47. In the middle of the recirculation pipe 54, an exhaust gas recirculation valve (EGR valve) 55 for adjusting the recirculation amount of exhaust gas is provided.
Is provided. The EGR valve 55 is controlled to open / close under the control of a vacuum switching valve (VSV) 56.

Further, in the middle of the intake pipe 47, there is provided a throttle valve 58 which is opened / closed in association with the depression amount of the accelerator pedal 57. Also, the throttle valve 5
A bypass passage 59 is provided in parallel with 8, and a bypass throttle valve 60 is provided in the bypass passage 59. The bypass throttle valve 60 is controlled to be opened / closed by an actuator 63 having a two-stage diaphragm chamber driven by the control of two VSVs 61 and 62. The bypass throttle valve 60 is controlled to open and close according to various operating states. For example, during idle operation, it is controlled to a half-open state to reduce noise and vibrations, during normal operation it is controlled to a fully open state, and when operation is stopped, it is controlled to a fully closed state for a smooth stop.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above.
3, TCV33, glow plug 46 and each VSV56,
61 and 62 are overflow timing calculation means, surplus angle calculation means,
The average rotation speed position time calculation means, rotation speed change calculation means, pulse time calculation means, angle time conversion means, overflow adjustment execution means, calculation rotation speed calculation means, calculation rotation speed correction means, and target injection amount calculation means Each of them is electrically connected to a constituent electronic control unit (hereinafter simply referred to as “ECU”) 71, and their drive timing is controlled by the ECU 71.

As the sensor constituting the operating condition detecting means of the diesel engine 2, the rotation speed sensor 35 described above is used.
In addition, the following various sensors are provided. That is,
An intake air temperature sensor 72 for detecting the intake air temperature THA is provided near the air cleaner 64 provided at the inlet of the intake pipe 47. Further, an accelerator opening sensor 73 for detecting the accelerator opening ACCP corresponding to the load of the diesel engine 2 is provided from the opening / closing position of the throttle valve 58. An intake pressure sensor 74 that detects the intake air pressure after supercharging by the turbocharger 49, that is, the supercharging pressure PiM is provided near the intake port 53. Further, a water temperature sensor 75 for detecting the cooling water temperature THW of the diesel engine 2 is provided. Further, a crank angle sensor 76 for detecting a rotation reference position of the crankshaft 40, for example, a rotation position of the crankshaft 40 with respect to a top dead center of a specific cylinder is provided. Furthermore, in a transmission (not shown), a vehicle speed sensor 77 for detecting a vehicle speed (vehicle speed) SP by turning on / off a reed switch 77b by a magnet 77a rotated by the rotation of the gear.
Is provided.

The above-mentioned sensors 72 to 77 are connected to the ECU 71, and the rotation speed sensor 3 is connected.
5 is connected. Further, the ECU 71 uses the sensors 35,
Based on the detection signals output from 72 to 77, the electromagnetic spill valve 23, the TCV 33, the glow plug 46 and the VSV 5
6, 61, 62 and the like are preferably controlled.

Next, the structure of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 includes a central processing unit (CPU) 81, a read-only memory (RO) in which a predetermined control program, maps and the like are stored in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing calculation results of the CPU 81, a backup RAM 84 for storing prestored data, and the like, and a bus 87 for connecting these units, an input port 85, an output port 86, and the like.
It is configured as a logical operation circuit connected by.
Here, the CPU 81 is adapted to perform a free running count operation for the calculation processing.

At the input port 85, the intake air temperature sensor 72, the accelerator opening sensor 73, the intake air pressure sensor 74 and the water temperature sensor 75 are connected to the buffers 88, 89, 90, 9 respectively.
1, the multiplexer 93, and the A / D converter 94. Similarly, the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 described above are connected to the input port 85 via a waveform shaping circuit 95. Then, the CPU 81 reads the detection signals of the sensors 35, 72 to 77, etc., which are input via the input port 85, as input values. Further, each drive circuit 9 is connected to the output port 86.
6,97,98,99,100,101 via electromagnetic spill valve 23, TCV33, glow plug 46 and VSV
56, 61, 62 and the like are connected.

Then, the CPU 81 controls the sensors 35 and 72.
Electromagnetic spill valve 2 based on input values read from ~ 77
3, TCV33, glow plug 46 and VSV56,6
1, 62 and the like are preferably controlled.

Next, the processing operation of the fuel injection amount control executed by the above-mentioned ECU 71 will be described with reference to FIGS. First, the flowchart of FIG.
"NE interrupt routine" which is interrupted at the rising edge of the engine rotation pulse of the engine rotation speed NE input from the rotation speed sensor 35 among the processes executed by the step 1.
Is shown.

When the processing shifts to this routine, first, at step 101, the current time FC at the time of the current NE interrupt obtained by the free running count operation and the interrupt time T0 corresponding to the current time at the time of the previous NE interrupt are set. The difference is set as the pulse time TNINT. That is, as shown in the time chart of FIG. 6, the time required to advance by the crank angle (11.25 ° CA) corresponding to one engine rotation pulse is calculated. In FIG. 6, one pulse from when the value of the pulse counter CNIRQ becomes “10” to when it becomes “11” is taken as an example.

Next, at step 102, it is judged if the value of the pulse counter CNIRQ is "13". Here, the value of the pulse counter CNIRQ is "1.
If it is not “3”, the process directly proceeds to step 104. On the other hand, the value of the pulse counter CNIRQ is "1.
If it is “3”, in step 103, the pulse time TNINT previously obtained in step 101 is set as the rotation increase time TN13. As shown in FIG. 6, the pulse riser time TN13 is the pulse counter C.
This corresponds to the pulse time TNINT required to advance the crank angle by “11.25 ° CA” from when the NIRQ value becomes “12” to “13”. In addition, the position of the time TN13 at the time of rotation increase is the diesel engine 2
In the same combustion cycle of, the instantaneous rotation speed of the engine rotation speed NE corresponds to the vicinity of the time when the rotation speed rises to the average rotation speed.

Then, step 102 or step 10
In step 104 after shifting from 3, it is determined whether or not the value of the pulse counter CNIRQ is "6".
Here, when the value of the pulse counter CNIRQ is not "6", the process directly proceeds to step 109.

On the other hand, when the value of the pulse counter CNIRQ is "6" in step 104, the pulse time TNINT previously obtained in step 101 is set as the rotation lowering time TN6 in step 105. As shown in FIG. 6, the rotation decrease time TN6 is "11.25 °" in crank angle from when the value of the pulse counter CNIRQ becomes "5" to when it becomes "6".
This corresponds to the pulse time TNINT required to advance by "CA". Further, the position of the time TN6 when the rotation speed is low corresponds to the vicinity of the time when the instantaneous rotation speed of the engine speed NE becomes the average rotation speed when the rotation speed is low in the same combustion cycle.

Then, in step 106, the difference between the rotation increasing time TN13 previously obtained in step 103 and the rotation decreasing time TN6 obtained in step 105 is calculated, and the calculated result is then calculated. It is set as a time difference ΔTN corresponding to the change in the rotation speed.

In step 107, the spill time pulse time T, which will be described later, is calculated from the set time difference ΔTN.
In step S1125, that is, the time correction coefficient KDT1 for correcting the time used to determine the target spill timing from the target spill angle is calculated. This time correction coefficient KDT
As shown in FIG. 7, 1 is obtained by referring to a map in which the relationship between the time difference ΔTN and the time correction coefficient KDT1 is predetermined. In this map, when the time difference ΔTN is positive, that is, when the engine rotation speed NE is rising and changing, the value of the time correction coefficient KDT1 is smaller than “1.0” in order to correct the spill time TS1125 small. Is also set small. Further, when the time difference ΔTN is negative, that is, when the engine rotation speed NE is changing downward, the value of the time correction coefficient KDT1 is larger than “1.0” in order to largely correct the spill time pulse TS1125. It is set.

Further, in step 108, a speed correction coefficient KNE for correcting a reference rotational speed NE1 which will be described later is calculated from the time difference ΔTN. As shown in FIG. 8, this speed correction coefficient KNE is obtained by referring to a map in which the relationship between the speed correction coefficient KNE and the time difference ΔTN is predetermined. In this map, when the time difference ΔTN is positive, that is, when the engine rotation speed NE is increasing and changed, the reference rotation speed NE1 is largely corrected,
The value of the speed correction coefficient KNE is set to be larger than "1.0". Further, when the time difference ΔTN is negative, that is, when the engine rotation speed NE is decreasing, the speed correction coefficient K is set to correct the reference rotation speed NE1 small.
The NE value is set smaller than “1.0”.

Then, step 104 or step 10
In step 109 after shifting from 8, it is determined whether or not the value of the pulse counter CNIRQ is "1".
Here, when the value of the pulse counter CNIRQ is not "1", the process directly proceeds to step 111. On the other hand, when the value of the pulse counter CNIRQ is “1”, in step 110, the reference rotation speed NE1
To calculate. As shown in FIG. 6, the reference rotation speed NE1 is equal to the pulse counter C in the same combustion cycle.
This corresponds to the instantaneous rotation speed in the pulse interval of "45 ° CA" in crank angle from when the NIRQ value becomes "13" until the next "1". At the same time, the position of the reference rotational speed NE1 corresponds to the vicinity of the timing when the instantaneous rotational speed of the engine rotational speed NE becomes the highest in the same combustion cycle and the timing when the fuel injection is started.

Then, step 109 or step 11
In step 111 after shifting from 0, it is determined whether or not the value of the pulse counter CNIRQ is "9".
Here, when the value of the pulse counter CNIRQ is not "9", the process directly proceeds to step 113. On the other hand, when the value of the pulse counter CNIRQ is “9”, in step 112, first in step 101
The pulse time TNINT obtained in step 1 is set as the spill time pulse time TS1125. As shown in FIG. 6, this spill pulse time TS1125 is required to advance the crank angle by “11.25 ° CA” from when the value of the pulse counter CNIRQ becomes “8” to “9”. It corresponds to the pulse time TNINT. At the same time, the position of the spill pulse time TS1125 corresponds to the vicinity of the time when the instantaneous rotation speed of the engine rotation speed NE becomes the minimum. Further, the position of the spill time pulse time TS1125 corresponds to the target spill angle which is the injection end timing in order to obtain the target injection amount determined according to the operating state of the diesel engine 2. Further, the spill pulse time TS1125 is used for predicting and determining the target spill timing in the next combustion cycle.

Then, step 111 or step 11
In step 113 after shifting from step 2, step 1
After setting the current time FC at 01 as the interrupt time T0, the subsequent processing is temporarily terminated.

Next, as described above, the time correction coefficient KDT1, the speed correction coefficient KNE, the reference rotation speed NE1 and the spill pulse time T which are obtained by the "NE interrupt routine" are described.
The processing operation of the fuel injection amount control performed using S1125 will be described.

The flowchart shown in FIG. 9 is a "main routine" for controlling the fuel injection amount in the fuel injection pump 1 among the processes executed by the ECU 71, and is executed by a regular interrupt every predetermined time.

When the processing shifts to this routine, first, at step 201, the accelerator opening ACCP is read based on the detection value of the accelerator opening sensor 73. Along with this, the time correction coefficient KDT1, the speed correction coefficient KNE, the reference rotation speed NE1 and the spill pulse time TS in the previous combustion cycle obtained in the "NE interrupt routine" are calculated.
1125 (i-1) is read.

Then, in step 202, the speed correction coefficient KNE and the reference rotational speed NE1 which have been read in previously are read.
From this, the calculation rotational speed NEQB is calculated. The calculation rotational speed NEQB is obtained by correcting the reference rotational speed NE1 in the same combustion cycle with the speed correction coefficient KNE to calculate the target injection amount and reflecting the rotational speed change. It is calculated according to the formula.

NEQB = NE1 * 4 * KNE Next, at step 203, the accelerator opening ACCP previously read and the previously calculated calculation rotational speed N.
With EQB, the final injection amount QFI as the target injection amount
Calculate N. This final injection amount QFIN is obtained according to a predetermined calculation formula.

Then, in step 204, the spill timing pulse number CANGLa and the surplus angle θREM are calculated based on the final injection amount QFIN previously obtained. The spill timing pulse number CANGLa and the remainder angle θREM are obtained with reference to the following calculation formulas.

QFIN = 11.25 × CANGLa + θREM In other words, as shown in FIG. 10, the final injection amount QFIN is “11.2” which corresponds to the angle of one engine rotation pulse.
5 ”and divide the quotient by the spill time pulse count CANG
It is obtained as La, and the remainder is obtained and set as the remainder angle θREM. Where spill time pulse number C
ANGLa uses the electromagnetic spill valve 2 to end fuel injection.
3 corresponds to the engine speed pulse number corresponding to the target spill timing at which the fuel should be turned off, that is, the fuel should be spilled ("8" in FIG. 10). Also, the remaining angle θREM
Is a value indicating the more strict target spill timing in terms of the spill timing pulse number CANGLa by angle.

Next, at step 205, the previously read spill pulse time TS1125 (i) previously read.
The spill pulse time after correction TS1125A is calculated from -1) and the time correction coefficient KDT1. The post-correction spill pulse time TS1125A is obtained by comparing the previous spill pulse time TS1125 (i-1) with the time correction coefficient KDT.
It is corrected by 1 to reflect the change in rotation speed, and is obtained according to the following calculation formula.

TS1125A = TS1125 (i−1) * KDT1 Then, in step 206, the surplus angle θREM previously obtained and the corrected spill pulse time TS1125 are obtained.
The spill time TSPONa at the spill time pulse number CANGLa is calculated from A. That is, the remainder angle θ
The REM is time-converted based on the corrected spill pulse time TS1125A. This spill time TSPO
Na is calculated according to the following calculation formula.

TSPONa = (θREM / 11.25) * TS112
5A After that, in step 207, the spill time TSPONa is set to a predetermined “88 μs” in order to prevent the delay due to the multiple interruption in consideration of the arithmetic processing speed by the ECU 71.
Is less than or equal to. Where spill time T
When SPONa is smaller than the predetermined “88 μs”, in step 208, as shown in FIG. 11, spill time pulse time TS after correction to spill time TSPONa
The result of adding 1125A is the final spill time TSPON
Set as. Further, in step 208, the result obtained by subtracting "1" from the spill timing pulse number CANGLa is set as the final spill timing pulse number CANGL. Then, in step 209, the electromagnetic spill valve 23 is turned off based on the set final spill timing pulse number CANGL and final spill time TSPON, and the end timing of fuel injection from the fuel injection pump 1, that is, the fuel injection amount is controlled. Then, the subsequent processing is temporarily terminated.

On the other hand, when the spill time TSPONa is equal to or longer than the predetermined "88 μs" in step 207, in step 210, the spill time TSPONa is directly changed to the final spill time TSP as shown in FIG.
Set as ON. Moreover, in the same step 210,
The spill timing pulse number CANGLa is set as it is as the final spill timing pulse number CANGL.

Then, in step 209, the electromagnetic spill valve 23 is turned off based on the set final spill timing pulse number CANGL and final spill time TSPON, and the end timing of fuel injection from the fuel injection pump 1 is reached.
That is, the fuel injection amount is controlled, and the subsequent processing is once ended.

The fuel injection amount control in the diesel engine 2 is executed as described above. And
In this embodiment, in order to convert the surplus angle θREM into time, the spill pulse time TS1125 near the previous target spill angle is not simply used, but the corrected spill pulse pulse TS1125 is corrected. Using time TS1125A. Moreover, in obtaining the corrected spill pulse time TS1125A, the crank angle required to rotate by a crank angle of one pulse in the vicinity of the average rotational speed position when the rotation is increased and when the rotation is decreased in the same combustion cycle. Time, that is, the rotation increasing time TN13 and the rotation decreasing time T
N6 is calculated respectively. Further, the time difference ΔTN corresponding to the change in the rotation speed at that time is calculated based on the calculated rotation increase time TN13 and rotation decrease time TN6. Then, based on the time correction coefficient KDT1 obtained corresponding to the calculated time difference ΔTN, the previous spill-time pulse time TS1125 is corrected, and the post-correction spill for one pulse in the vicinity of the target spill angle of the next combustion cycle is performed. The pulse time TS1125A is predicted and calculated.

Therefore, for example, when the diesel engine 2 is decelerated, as shown in FIG. 13, even when the engine speed NE is greatly reduced, the spill pulse time TS1125 (i-1) in the previous combustion cycle is set to the time difference. Since the correction is performed based on ΔTN, the post-correction spill-time pulse time TS1125A to be used in the present combustion cycle is appropriately predicted and calculated according to the change in the rotation speed. Then, since the surplus angle θREM is converted into time by the properly predicted post-correction spill time TS1125A, the time conversion can be performed with higher accuracy. As a result, the time timing for executing the fuel spill can be more accurately determined according to the decrease in the engine speed NE. Therefore, the execution of the end of fuel injection is performed more accurately,
The required target injection amount can be obtained more accurately.

In addition, in this embodiment, the reference rotational speed NE1 is obtained near the time when the instantaneous rotational speed of the engine rotational speed NE is the highest in the same combustion cycle and near the time when fuel injection is started. The reference rotation speed NE1 is used as a calculation rotation speed for calculating the final injection amount QFIN as the target injection amount. Moreover, by correcting the reference rotational speed NE1 based on the time difference ΔTN at that time, the operational rotational speed NEQB corresponding to the change in the engine rotational speed NE is predicted and obtained.
Then, the calculation rotational speed NEQB and the accelerator opening A
The final injection amount QFIN is calculated and determined based on CCP.

Therefore, the final injection amount QFIN itself is
It is calculated based on the calculation rotational speed NEQB that matches the engine rotational speed NE when the fuel injection is actually performed. Moreover, the final injection amount QFIN is obtained based on the calculation rotational speed NEQB that predicts the change in the engine rotational speed NE in the current combustion cycle. As a result, as shown in FIG. 13, even when the decrease in the engine speed NE is large, an appropriate final injection amount QFI suitable for the engine speed NE when the fuel injection is actually performed is performed.
N can be obtained.

Similarly, even when the engine speed NE significantly increases during acceleration of the diesel engine 2, the remainder based on the corrected spill pulse time TS1125A properly predicted in accordance with the increase in the engine speed NE. The time conversion of the angle θREM can be performed with higher accuracy. Therefore, the time timing for executing the fuel spill can be more accurately determined according to the increase in the engine rotation speed NE, and the fuel injection end can be executed more accurately. Further, since the final injection amount QFIN itself is calculated based on the calculation rotational speed NEQB that predicts the change in the engine rotational speed NE in the present combustion cycle, even if the engine rotational speed NE is greatly increased, the fuel injection is actually performed. It is possible to obtain an appropriate final injection amount QFIN that is suitable for the engine rotation speed NE when the fuel injection is performed.

Therefore, the fuel injection amount control of the diesel engine 2 can be performed with higher accuracy, and the occurrence of crimp or surge in the diesel engine 2 can be prevented in advance. Furthermore, when the engine speed NE decreases, the decrease is promptly and accurately predicted to determine the final injection amount QF.
Since it can be reflected in the calculation of IN, the engine stalling resistance of the diesel engine 2 can also be improved.

The present invention is not limited to the above-described embodiment, but may be implemented as follows with a part of the structure appropriately changed without departing from the spirit of the invention. (1) In the above-described embodiment, the value of the pulse counter CNIRQ is “crank angle time required to rotate by a constant crank angle in the vicinity of the average rotation speed position when the rotation is increased and when the rotation is decreased in the same combustion cycle. 1
Rotational rise time TN from 2 ”to 13”
13 and the rotation decrease time TN6 from when the value of the pulse counter CNIRQ changes from "5" to "6" are used, but the invention is not limited to this. For example, the rotation increase time TN12 during which the value of the pulse counter CNIRQ changes from “11” to “12” and the decrease of rotation during the time when the value of the pulse counter CNIRQ changes from “6” to “7”. Time TN7 may be used.

(2) In the above embodiment, as the rotation speed used for calculating the target injection amount, from the time when the value of the pulse counter CNIRQ becomes "13" to the next "1" in the same combustion cycle. Reference speed NE between
However, the pulse counter CNIRQ is not limited to this, for example, in the same combustion cycle.
It is also possible to appropriately select and use the instantaneous rotation speed from “13” to “4” with the value of.

(3) In the above embodiment, the diesel engine 2 having the turbocharger 49 as the supercharger is embodied, but the diesel engine having the supercharger as the supercharger and the supercharger are provided. It can also be embodied in not a diesel engine.

[0071]

As described above in detail, according to the present invention, the instantaneous rotation speed at the predetermined crank angle position in the same combustion cycle is obtained as the calculation rotation speed for calculating the target injection amount, and the calculation is performed. The target rotation speed is corrected based on the rotation speed change, and the target injection amount is calculated and determined based on the corrected calculation rotation speed, etc., so it is based on the rotation speed that predicts the rotation speed change in this combustion cycle. Since the target injection amount is determined and the fuel injection amount control is executed, the target injection amount suitable for the rotation speed at which fuel injection is actually performed is determined even when the rotation speed of the diesel engine changes greatly. It is possible to control the fuel injection amount based on the target injection amount,
As a result, it has the excellent effect of being able to prevent the occurrence of surges and surges in diesel engines.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a fuel injection amount control device for a diesel engine with a supercharger in one embodiment embodying the present invention.

FIG. 3 is a cross-sectional view showing a fuel injection pump in one embodiment.

FIG. 4 is a block diagram showing an electrical configuration of an ECU in one embodiment.

FIG. 5 is a flowchart illustrating an NE interrupt routine executed by the ECU and interrupted at the rising edge of an engine rotation pulse in one embodiment.

FIG. 6 is a time chart for explaining a correspondence relationship between a change in engine rotation speed and an engine rotation pulse in the embodiment.

FIG. 7 is a map in which a relationship between a time correction coefficient and a time difference is predetermined in one embodiment.

FIG. 8 is a map in which a relationship of a speed correction coefficient with respect to a time difference is predetermined in one embodiment.

FIG. 9 is a flowchart illustrating a “main routine” for controlling a fuel injection amount executed by an ECU in one embodiment.

FIG. 10 is a time chart for explaining a correspondence relationship between an engine rotation pulse and an electromagnetic spill valve operation, the number of spill timing pulses according to a final injection amount, a final spill time, and the like in one embodiment.

FIG. 11 is a time chart illustrating a correspondence relationship between an engine rotation pulse and an electromagnetic spill valve operation when the spill time is smaller than 88 μs, a final spill time pulse number, a final spill time, and the like in one embodiment.

FIG. 12 is a time chart for explaining a correspondence relationship between an engine rotation pulse and an electromagnetic spill valve operation when the spill time is 88 μs or more, a final spill time pulse number, a final spill time, and the like in one embodiment.

FIG. 13 is a time chart illustrating a correspondence relationship between an engine rotation speed change and an engine rotation pulse during deceleration in one embodiment.

FIG. 14 is a time chart illustrating a correspondence relationship between a change in engine rotation speed and an engine rotation pulse in a conventional example.

[Explanation of symbols]

1 ... Fuel injection pump, 2 ... Diesel engine, 12 ...
Plunger, 15 ... High pressure chamber, 23 ... Electromagnetic spill valve as overflow adjusting valve, 35 ... Rotation speed sensor as engine rotation detecting means, 71 ... ECU (overflow timing calculating means, surplus angle calculating means, average rotational speed position) The time calculation means, the rotation speed change calculation means, the pulse time calculation means, the angle time conversion means, the overflow adjustment execution means, the calculation rotation speed calculation means, the calculation rotation speed correction means, and the target injection amount calculation means are configured. ).

Claims (1)

[Claims] 1. A fuel injection pump for pumping and injecting fuel pressurized in a high pressure chamber to a diesel engine by a plunger that is reciprocally driven in association with rotation of a diesel engine, and fuel injection from the fuel injection pump. An overflow adjustment valve that is opened to end the pressurization of fuel in the high pressure chamber to adjust the amount and adjusts the overflow of fuel from the high pressure chamber, and is determined according to the operating state of the diesel engine. An overflow timing calculating means for calculating a target overflow timing corresponding to the injection end timing in order to obtain the target injection amount, and an engine rotation pulse for detecting the engine rotation pulse for each constant crank angle of the diesel engine. Engine rotation detecting means for detecting an instantaneous rotation speed for each pulse; and engine rotation pulses sequentially detected by the engine rotation detecting means. When the engine rotation pulse is at a certain reference position to the target overflow timing calculated by the overflow timing calculation means, the engine rotation pulse count number and the surplus angle calculation means for calculating the surplus angle less than one pulse thereof are calculated. Based on the engine rotation pulse detected by the engine rotation detection means, the diesel engine rotates by a constant crank angle in the vicinity of each average rotation speed position when the rotation speed increases and when the rotation speed decreases in the same combustion cycle. An average position time calculating means for calculating each required crank angle time, and a rotation calculating a change in rotation speed at that time based on the crank angle times at the time of rotation increase and at the time of rotation decrease calculated by the average position time calculation means. Speed change calculation means and engine detected by the engine rotation detection means A pulse time for predictively calculating the required time for one pulse corresponding to the target overflow timing calculated by the overflow timing calculating means, based on the rotation pulse and the rotation speed change calculated by the rotation speed change calculating means. Calculating means, an angle time converting means for converting the remainder angle calculated by the remainder angle calculating means into time based on the required time for one pulse predicted and calculated by the pulse time calculating means; A time determined from the count number of engine rotation pulses up to the target overflow timing calculated by the surplus angle calculation means and the time conversion value of the surplus angle by the angle time conversion means in order to execute the fuel overflow. A fuel injection amount control device for a diesel engine, comprising: an overflow adjustment executing means for opening the overflow adjustment valve according to a timing. Based on the instantaneous rotation speed for each engine rotation pulse detected by the gin rotation detection means, the instantaneous rotation speed at a predetermined crank angle position within the same combustion cycle of the diesel engine is used for calculating the target injection amount. Rotational speed calculation means for calculating as rotational speed, and rotational speed for calculation calculated by the rotational speed calculation means for calculation are corrected based on the rotational speed change calculated by the rotational speed change calculation means. A diesel engine comprising speed correction means and target injection amount calculation means for calculating and determining the target injection amount based on the corrected calculation rotation speed and the like corrected by the calculation rotation speed correction means. Fuel injection amount control device.