JP2743591B2 - Fuel injection control system 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 injection control device for a diesel engine applied to, for example, an automobile.

[0002]

2. Description of the Related Art Conventionally, various injection pumps have been used to inject a required amount of fuel from an injection pump in order to improve the fuel efficiency of a diesel engine, maintain suitable output characteristics, and prevent the generation of smoke. Fuel injection amount control is being performed. For example, in Japanese Patent Application Laid-Open No. 1-290945, fluctuations in injection amount due to aging of a fuel injection pump or a diesel engine, and fuel temperature (fuel fluidity) are described.
The fuel injection amount control for compensating the fluctuation of the injection amount due to the change of the fuel injection amount is performed. That is, in a stable operation state during idle speed control (ISC),
For a plurality of different fuel temperature states, ISC describes the change characteristics of the operating state quantity with respect to the fuel quantity actually supplied to the combustion chamber.
It is calculated as a control amount. That is, an ISC control amount corresponding to a change characteristic of a fuel leak amount (amount of leakage) with respect to a change in fuel temperature is calculated. Then, the fuel injection amount in another operating state is corrected based on the ISC control amount.

[0003]

However, in the above-mentioned prior art, in addition to the change in the injection amount due to the aging with a small temporal variation, the influence of the fuel temperature having a large temporal variation is surely ensured. In order to take in, a high learning speed was required for calculating the ISC control amount. And, the faster the learning speed of the ISC control amount is, the more likely it is to be affected by the fluctuation of the air conditioner load at that time or the load fluctuation by the electric system. Therefore, if the ISC control amount is simply calculated at a high learning speed, the fuel injection amount corrected in an operating state other than the idle state may deviate from the preferable injection amount. That is, there is a possibility that an error occurs in the correction of the fuel injection amount.

[0004] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is not to be affected by temporary load fluctuations caused by devices such as an air conditioner interlocked with a diesel engine, and to prevent aging and fuel consumption. An object of the present invention is to provide a fuel injection amount control device for a diesel engine capable of appropriately correcting a fuel injection amount by compensating for a change in the injection amount due to a temperature change.

[0005]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, fuel injection means M2 for injecting fuel into a diesel engine M1,
An operating state detecting means M3 for detecting an operating state of the diesel engine M1, a fuel injection amount calculating means M4 for calculating a fuel injection amount to be injected into the diesel engine M1 based on a detection result of the operating state detecting means M3; The fuel injection means M based on the calculation result of the fuel injection amount calculation means M4
A fuel temperature control device for detecting the temperature of the fuel injected from the fuel injection device M2 to the diesel engine M1; The fuel temperature correction value calculation means M7 for calculating a fuel temperature correction value for correcting the fuel injection amount based on the detection result of the fuel temperature detection means M6, and the diesel engine M1 based on the detection result of the operating state detection means M3 A change characteristic calculating means M8 for calculating a change characteristic of an operation state quantity caused by an amount of fuel actually supplied to the diesel engine M1 in a predetermined stable operation state; a calculation result of the change characteristic calculation means M8; Based on the detection result of the temperature detecting means M6, the non-fuel temperature change characteristic in which the influence of the fuel temperature is excluded from the change characteristic of the operation state quantity is obtained. The non-fuel temperature change characteristic calculating means M9 to calculate the non-fuel temperature correction value for correcting the fuel injection amount based on the calculation result of the non-fuel temperature change characteristic calculating means M9. Non-fuel temperature correction value calculating means M10 that performs learning calculation at a slow speed capable of eliminating load fluctuations, based on the calculation result of the non-fuel temperature correction value calculation means M10 and the calculation result of fuel temperature correction value calculation means M7. , Fuel injection amount calculating means M
And a fuel injection amount correction calculating means M11 for correcting and calculating the fuel injection amount calculated by step 4.

[0006]

According to the above arrangement, as shown in FIG. 1, the operating state detecting means M3 detects the operating state of the diesel engine M1 during the operation of the diesel engine M1. Further, based on the detection result, the fuel injection amount calculating means M4 calculates the fuel injection amount to be injected into the diesel engine M1.

The change characteristic calculation means M8 is actually supplied to the diesel engine M1 when the diesel engine M1 is in a predetermined stable operation state, for example, an idle operation state, based on the detection result of the operation state detection means M3. A change characteristic of the operation state quantity caused by the fuel quantity is calculated.
Further, the fuel temperature detecting means M6 detects the temperature (fuel temperature) of the fuel injected into the diesel engine M1. At this time, based on the detection result of the fuel temperature, the fuel temperature correction value calculation means M7 calculates a fuel temperature correction value for correcting the fuel injection amount. The non-fuel temperature change characteristic calculating means M9
Calculates a non-fuel temperature change characteristic which excludes the influence of the fuel temperature from the change characteristic of the operating state quantity based on the calculation result of the change characteristic calculation means M8 and the detection result of the fuel temperature detection means M6. Further, based on the calculation result of the non-fuel temperature change characteristic, the non-fuel temperature correction value calculation means M10 calculates a non-fuel temperature correction value for correcting the fuel injection amount by using a load variation caused by devices linked to the diesel engine M1. The learning operation is performed at a slow speed that can eliminate.

Then, the fuel injection amount correction calculating means M11
Is calculated by the fuel injection amount calculating means M4 based on the fuel temperature correction value calculated by the fuel temperature correction value calculating means M7 and the non-fuel temperature correction value calculated by the non-fuel temperature correction value calculating means M10. The calculated fuel injection amount is corrected.
Therefore, the fuel injection control means M5 controls the drive of the fuel injection means M2 based on the corrected fuel injection amount,
Control of the fuel injection amount to the diesel engine M1 is performed.

Therefore, since the non-fuel temperature correction value is learned and calculated at a slow speed, the non-fuel temperature correction value is not affected by load fluctuations or the like caused by other devices having large temporal fluctuations. It is calculated as a value that takes into account the effects of aging with small fluctuations. Therefore, in the fuel injection amount correction calculating means M11, the fuel injection amount can be properly adjusted by the separate correction values of the fuel temperature correction value taking into account the influence of the fuel temperature and the non-fuel temperature correction value taking into account the effects of aging. Correction calculation is performed, and appropriate fuel injection amount control is always performed.

[0010]

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 in detail with reference to the drawings. FIG. 2 is a schematic configuration diagram showing a fuel injection amount control device for a supercharged diesel engine in this embodiment, and FIG. 3 is a sectional view showing a distribution type fuel injection pump 1 constituting the fuel injection means. The fuel injection pump 1 includes a drive pulley 3 which is drivingly connected to a crankshaft 40 of the diesel engine 2 via a belt or the like. The fuel injection pump 1 is driven by the rotation of the drive pulley 3, and the fuel is injected under pressure to each fuel injection nozzle 4 provided for each cylinder (four cylinders in this case) of the diesel engine 2 to perform fuel injection. .

In the fuel injection pump 1, a drive pulley 3 is attached to a tip of a drive shaft 5.
In the middle of the drive shaft 5, there is provided a fuel feed pump (developed at 90 degrees in this figure) 6 composed of a vane type pump. Further, a disk-shaped pulser 7 is attached to the base end side of the drive shaft 5. The outer surface of the pulsar 7 has a diesel engine 2
In this case, four cutting teeth are formed at equal angular intervals, that is, four cutting teeth are formed at equal angular intervals, and between each cutting tooth, 14 (total of 56) projections are formed at equal angular intervals. I have. 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 facing the cam face 8a of the cam plate 8 are mounted along the circumference of the roller ring 9. I have. Cam face 8
a is provided as many as the number of cylinders of the diesel engine 2. The cam plate 8 is always urged and engaged with the cam roller 10 by the spring 11.

A base end of a fuel pressurizing plunger 12 is integrally rotatably mounted on the cam plate 8, and the cam plate 8 and the plunger 12 are rotated in conjunction with the rotation of the drive shaft 5. That is, the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via the coupling, so that the cam plate 8 rotates and engages with the cam roller 10 to reciprocate in the left-right direction by the same number as the number of cylinders. Driven. Further, the plunger 12 is driven to reciprocate in the same direction while rotating with the reciprocation. That is,
The plunger 12 is moved forward (lift) while the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, and conversely, the plunger 12 is moved back while the cam face 8a rides down the cam roller 10.

The plunger 12 is fitted into a cylinder 14 formed in a pump housing 13, and a high pressure chamber 15 is formed between a tip surface of the plunger 12 and a bottom surface of the cylinder 14.
It has become. Also, on the outer periphery of the tip 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. In addition, these suction grooves 16
And the pump housing 13 corresponding to the distribution port 17.
Is formed with a distribution passage 18 and a suction port 19.

When the drive shaft 5 is rotated and the fuel feed pump 6 is driven, fuel is supplied from a fuel tank (not shown) into the fuel chamber 21 through the fuel supply port 20. Also, during the suction stroke in which the plunger 12 is moved back and the high-pressure chamber 15 is depressurized, the suction groove 1
The fuel is introduced from the fuel chamber 21 to the high-pressure chamber 15 when one of the ports 6 communicates 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 from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder and injected.

A spill passage 22 for fuel overflow that connects the high-pressure chamber 15 and the fuel chamber 21 is provided in the pump housing 13.
Are formed. In the middle of the spill passage 22, there is provided a well-known electromagnetic spill valve 23 for injection adjustment.
This electromagnetic spill valve 23 is a normally open type valve, and a coil 24
Is in a non-energized (off) state, the valve body 25 is opened, and the fuel in the high-pressure chamber 15 overflows to the fuel chamber 21. When the coil 24 is energized (turned on), the valve body 25 is closed, and the overflow 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 controlled to close and open, and the overflow of the fuel from the high-pressure chamber 15 to the fuel chamber 21 is regulated. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel in the high-pressure chamber 15 is reduced in pressure, and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even when the plunger 12 moves forward, the fuel pressure in the high-pressure chamber 15 does not increase while the electromagnetic spill valve 23 is open, and the fuel injection from the fuel injection nozzle 4 is not performed. Further, during the forward movement of the plunger 12, by controlling the timing of closing and opening the electromagnetic spill valve 23, the amount of fuel injected from the fuel injection nozzle 4 is controlled.

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

The timer device 26 is operated by 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. A timer spring 31 for urging the piston 28 toward the other pressurizing chamber 30 is provided. The timer piston 28 is connected to the roller ring 9 via the slide pin 32.
It is connected to the.

In the pressurizing chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. The position of the timer piston 28 is determined by the balance between the fuel pressure and the urging force of the timer spring 31. Further, the position of the roller ring 9 is determined by determining the position of the timer piston 28, and the plunger 1 is moved through the cam plate 8.
2 is determined.

In order to control the fuel pressure of the timer device 26, the timer device 26 is provided with a timing control valve 33. That is, the pressurizing chamber 30 and the low-pressure chamber 29 of the timer housing 27 are communicated by the communication passage 34, and the timing control valve 33 is provided in the communication passage 34. The timing control valve 33 is an electromagnetic valve whose opening and closing are controlled by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by controlling the opening and closing of the valve 33.
Then, the lift timing of the plunger 12 is controlled by the fuel pressure adjustment, and the fuel injection timing from each fuel injection nozzle 4 is adjusted.

On the upper part of the roller ring 9, a rotation speed sensor 35 composed of an electromagnetic pickup coil is mounted so as to face the outer peripheral surface of the pulser 7. This rotation speed sensor 35
Detects the passage of a projection or the like of the pulsar 7 when they cross, and outputs a timing signal (engine rotation pulse) corresponding to the engine speed NE. Further, since the rotation speed sensor 35 is integrated with the roller ring 9, the rotation speed sensor 35 outputs a reference timing signal to the plunger lift at a constant timing regardless of the control operation of the timer device 26.

The pump housing 13 includes the fuel chamber 2.
A fuel temperature sensor 36 is provided as fuel temperature detecting means for detecting the fuel temperature TF in the fuel cell 1. 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. Each of the main combustion chambers 44 is connected to a sub-combustion chamber 45 provided correspondingly for each cylinder. Then, the fuel injected from each fuel injection nozzle 4 is supplied to each sub combustion chamber 45. Also, each sub-combustion chamber 4
5 includes a well-known glow plug 46 as a starting assist device.
Are respectively attached.

The diesel engine 2 is provided with an intake pipe 47 and an exhaust pipe 50. The intake pipe 47 is provided with a compressor 49 of a turbocharger 48 constituting a supercharger, and the exhaust pipe 50 is provided with a turbocharger. 48
Turbine 51 is provided. Further, a waste gate valve 5 for adjusting the supercharging pressure PiM is provided in the exhaust pipe 50.
2 are provided. As is well known, the turbocharger 48 uses the energy of the exhaust gas to rotate the turbine 51, and rotates the compressor 49 on the same axis to increase the pressure of the intake air. Thus, a high-density air-fuel mixture is sent into the main combustion chamber 44 to burn a large amount of fuel, thereby increasing the output of the diesel engine 2.

The diesel engine 2 has an exhaust pipe 5
A recirculation pipe 54 is provided for recirculating a part of the exhaust gas in the cylinder 0 to the suction port 53 of the intake pipe 47. An exhaust gas recirculation valve (EGR valve) 55 for adjusting the amount of exhaust gas recirculation is provided in the middle of the recirculation pipe 54. The opening and closing of the EGR valve 55 is controlled by the control of a vacuum switching valve (VSV) 56.

Further, a throttle valve 58 that opens and closes in conjunction with the amount of depression of an accelerator pedal 57 is provided in the middle of the intake pipe 47. Also, its 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 opening and closing of the bypass throttle valve 60 is controlled by an actuator 63 having a two-stage diaphragm chamber driven by control of two VSVs 61 and 62. The opening and closing of the bypass throttle valve 60 is controlled in accordance with various operation states. For example, it is controlled to a half-open state during idle operation to reduce noise and vibration, to a fully opened state during normal operation, and to a fully closed state during smooth operation to stop smoothly.

The electromagnetic spill valve 2 provided in the fuel injection pump 1 and the diesel engine 2 as described above
3. The timing control valve 33, the glow plug 46, and each of the VSVs 56, 61, 62 include fuel injection amount calculating means, fuel injection control means, fuel temperature correction value calculating means, change characteristic calculating means, non-fuel temperature change characteristic calculating means, The ECU 71 is electrically connected to an electronic control unit (hereinafter, simply referred to as “ECU”) 71 that constitutes the non-fuel temperature correction value calculation unit and the fuel injection amount correction calculation unit, and the ECU 71 controls the drive timing.

As sensors constituting the operating state detecting means, the following various sensors are provided in addition to the rotation speed sensor 35. That is, an intake air temperature sensor 7 for detecting an intake air temperature THA near the air cleaner 64 is provided in the intake pipe 47.
2 are provided. Further, an accelerator opening sensor 73 for detecting the accelerator opening ACCP corresponding to the load of the diesel engine 2 from the open / close position of the throttle valve 58 is provided. An intake pressure sensor 74 for detecting the intake air pressure after being supercharged by the turbocharger 48, that is, the supercharging pressure PiM, is provided near the intake port 53. Further, 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 of the diesel engine 2, for example, a rotation position of the crankshaft 40 with respect to a top dead center of a specific cylinder is provided.
Further, in a transmission (not shown), a reed switch 77b is turned on / off by a magnet 77a which is rotated by the rotation of the gear, so that the vehicle speed (vehicle speed) S
A vehicle speed sensor 77 for detecting P is provided.

The ECU 71 is connected to each of the sensors 72 to 77 described above,
5 and the fuel temperature sensor 36 are connected. Also, ECU7
Reference numeral 1 denotes an electromagnetic spill valve 23, a timing control valve 33, a glow plug 46, and a VSV 56, 6 based on signals output from the sensors 35, 36, 72 to 77.
1, 62, etc. are suitably controlled.

Next, the configuration of the ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 has a central processing unit (CPU) 81, a read-only memory (RO) storing a predetermined control program, a map, and the like in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing the operation results and the like of the CPU 81, a backup RAM 84 for storing previously stored data, and the like, and a bus 87 for connecting these components to the input port 85 and the output port 86.
Are configured as logical operation circuits connected with each other.

The input port 85 has the above-described intake air temperature sensor 72, accelerator opening sensor 73, intake pressure sensor 74,
The water temperature sensor 75 and the fuel temperature sensor 36
8, 89, 90, 91 and 92, a multiplexer 93 and an A / D converter 94. Similarly, the input port 85 is provided with the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 described above.
5 are connected. Then, the CPU 81 controls each of the sensors 35, 36, 7 inputted through the input port 85.
A detection signal such as 2 to 77 is read as an input value. The output ports 86 are connected to the respective drive circuits 96, 97, 98, 99,
100, 101, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, and the VSV
56, 61, 62, etc. are connected.

Then, the CPU 81 controls the sensors 35, 3
The electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSVs 56, 61, 62 and the like are suitably controlled based on the input values read from 6, 72 to 77. Next, a processing operation of the fuel injection amount control executed by the above-described ECU 71 will be described with reference to flowcharts shown in FIGS. 5, 7, and 10, maps shown in FIGS.

First, the flowchart shown in FIG.
71 is a routine for calculating an integral control amount NFI used for idle speed control (ISC) control in a stable idling state of the diesel engine 2 among the processes executed by the diesel engine 2.
It is executed by a periodic interrupt every 9 msec. When the process proceeds to this routine, first, in step 101, the accelerator opening ACCP, the vehicle speed SP, and the engine speed NE are read based on the detected values of the accelerator opening sensor 73, the vehicle speed sensor 77, the rotation speed sensor 35, and the like. .

Subsequently, in step 102, it is determined whether or not the vehicle is in the idle stable state. This determination is made based on whether or not the accelerator opening ACCP previously read is “0%” and the vehicle speed SP is “0 km / h” after a predetermined time has elapsed after the start of the diesel engine 2. If it is not in the idling stable state, the process is temporarily terminated. If the engine is in the idling stable state, it is determined in step 103 whether or not the actual engine speed NE previously read after the start of the diesel engine 2 is equal to the target engine speed NF in the idling stable state. . And the actual engine speed N
If E is equal to the target rotation speed NF, the process is temporarily terminated. If the actual engine speed NE is not equal to the target engine speed NF, the routine proceeds to step 104.

In step 104, the integral correction amount ΔNFI is obtained from the absolute value of the difference between the actual engine speed NE and the target speed NF. This integral correction amount ΔNFI is obtained by referring to a predetermined map as shown in FIG. Thereafter, in step 105, it is determined whether or not the actual engine speed NE is higher than the target engine speed NF.

If the actual engine speed NE is higher than the target engine speed NF, at step 106, the integral control amount NFI obtained in the previous control cycle is obtained.
The result obtained by subtracting the integral correction amount ΔNFI from 0 is set as the current integral control amount NFI, and the process is temporarily terminated. or,
If the actual engine speed NE is not higher than the target engine speed NF, in step 107, the integral control amount NFI0 obtained in the previous control cycle is added to the integral correction amount ΔFIO.
The result obtained by adding the NFI is set as the current integral control amount NFI, and the process is temporarily terminated.

As described above, the calculation of the integral control amount NFI used for the ISC control is executed. FIG. 7 shows a fuel temperature correction coefficient KTF as a fuel temperature correction value used for calculating the maximum injection amount QFULL and an integration as a non-fuel temperature correction value excluding the influence of the fuel temperature in the idling stable state of the diesel engine 2. This is a routine for calculating the control correction coefficient KNFI. In this embodiment, the routine is executed by a periodic interruption every 1 second.

When the process proceeds to this routine, first, in step 201, the fuel temperature TF, the engine speed NE, and the cooling water temperature THW are respectively determined based on the detected values of the fuel temperature sensor 36, the rotation speed sensor 35, and the water temperature sensor 75. Read. Then, in step 202, a fuel temperature correction coefficient KTF is calculated based on the read fuel temperature TF and the engine speed NE. The fuel temperature correction coefficient KTF is a coefficient for correcting the maximum injection amount QFULL simply according to the magnitude of the fuel temperature TF, and refers to a predetermined two-dimensional map as shown in FIG. Desired. As is clear from this two-dimensional map, in this embodiment, when the fuel temperature TF is low, the maximum injection amount QFULL
The fuel temperature correction coefficient KTF is set so that the maximum injection amount QFULL is corrected to be large when the fuel temperature TF is high, and the correction value is changed in accordance with the engine speed NE. I have.

Subsequently, in step 203, the integral control amount NFI obtained by the routine of FIG. 5 and the fuel temperature TF previously obtained are corrected with reference to the following equation (1). Is corrected and calculated. The corrected integrated control amount NFI1 is a value obtained by removing the influence of the change in the fuel temperature TF from the integrated control amount NFI before correction. In the equation (1), “C” is an arbitrary constant.

NFI1 = NFI + C (TF-40)
(1) Next, in step 204, it is determined whether or not the previously read value of the cooling water temperature THW is a high temperature of “60 ° C.” or more. Then, if the value of the cooling water temperature THW is not equal to or higher than “60 ° C.”, the process is temporarily terminated. If the value of the cooling water temperature THW is equal to or higher than “60 ° C.”, it is determined in step 205 whether the previously read engine speed NE is higher than “500 rpm”.

When the engine speed NE is "500r
If it is not larger than "pm", the process is temporarily terminated. When the engine speed NE is larger than "500 rpm", the learning value NFIG for injection amount correction is obtained.
The process proceeds to step 206 assuming that the learning condition for (the unit is “rpm”) is satisfied. Step 206
, The learning value NFIG0 in the previous control cycle
It is determined whether or not (the unit is “rpm”) is larger than the corrected integral control amount NFI1 previously obtained. When the learning value NFIG0 is larger than the integral control amount NFI1, in step 207, the learning value NFIG0 is extremely smaller than the learning value NFIG0 in the previous control cycle by "1 (rp).
m) ”is set as the updated learning value NFIG. On the other hand, if the learning value NFIG0 is not larger than the integral control amount NFI in step 206, in step 208, the learning obtained by adding "1 (rpm)" to the learning value NFIG0 in the previous control cycle is updated. Set as value NFIG.

Then, step 207 or step 20
8, the process proceeds to step 209, where the integral control correction coefficient KNFI is calculated based on the updated learning value NFIG and the engine speed NE, and the process is terminated once. This integral control correction coefficient KNFI is a coefficient for correcting the maximum injection amount QFULL in accordance with the amount of fluctuation due to the aging of the fuel injection pump 1 or the difference in fuel properties (the original quality of fuel). As shown in FIG. 9, it is obtained by referring to a predetermined two-dimensional map. As is apparent from this two-dimensional map, in this embodiment, the maximum injection amount QFULL is corrected to be small when the learning value NFIG is small, and the maximum injection amount QFULL is corrected to be large when the learning value NFIG is large. The integral control correction coefficient KNFI is changed so that the value is changed according to the magnitude of the engine speed NE.
Is set.

As described above, the fuel temperature correction coefficient KTF and the integral control correction coefficient KNF used to calculate the maximum injection amount QFULL
The calculation of I is performed. That is, in this embodiment, the fuel temperature correction coefficient KTF that reflects the fuel temperature TF having a large temporal variation is calculated every control cycle of 1 second. Further, in this embodiment, the integral control correction coefficient KNFI which reflects the secular change of the fuel injection pump 1 or the diesel engine 2 or the difference in fuel properties, which is small in temporal fluctuation and in which the influence of the fuel temperature TF is eliminated, is used. The learning value NFIG for the calculation is adjusted by an extremely small "1" every 1 second control cycle. Therefore, FIG.
Of the integral control correction coefficient KNFI calculated with reference to the two-dimensional map is updated at a slow speed on the order of one day or two days.

On the other hand, the flowchart shown in FIG.
The main routine for controlling the fuel injection amount during the operation of the diesel engine 2 among the processes executed by U71 is shown. When the process proceeds to this routine, first, in step 301, the rotation speed sensor 35,
The engine speed NE, the accelerator opening ACCP, and the supercharging pressure PiM are read from the detected values of the accelerator opening sensor 73 and the intake pressure sensor 74, respectively.

Next, at step 302, a basic fuel injection amount QBASE is calculated based on the read engine speed NE, accelerator opening ACCP and the like. The calculation of the basic injection amount QBASE is performed with reference to a predetermined map (not shown) using the engine speed NE and the accelerator opening ACCP as parameters. In addition, in the calculation of the basic injection amount QBASE, the low temperature start increase correction, the acceleration increase correction, the rapid deceleration increase correction, etc. are performed based on the values of the coolant temperature THW, the accelerator opening ACCP, the engine speed NE, and the like as necessary. Is performed.

Thereafter, in step 303, the basic maximum injection amount Q is calculated based on the previously read engine speed NE.
Find SPF0. This basic maximum injection amount QSPF0 is obtained by referring to a predetermined map as shown in FIG.
In step 304, the maximum injection increase amount QSPF1 is obtained from the engine speed NE. This maximum injection increase QSP
F1 is obtained by referring to a predetermined map as shown in FIG.

Further, in step 305, an intake pressure correction coefficient K2 is obtained from the read supercharging pressure PiM.
The intake pressure correction coefficient K2 is obtained by referring to a predetermined map as shown in FIG. Then, in step 306, the basic maximum injection amount QSPF obtained earlier is obtained.
The maximum injection amount QFULL is calculated from 0, the maximum injection increase amount QSPF1, the intake pressure correction coefficient K2, and the fuel temperature correction coefficient KTF and the integral control correction coefficient KNFI obtained in the routine of FIG. This calculation is performed according to the following equation (2).

QFULL = (K2 × QSPF1 + QSPF0) × KTF × KNFI (2) Then, in step 307, the previous step 302
It is determined whether or not the basic injection amount QBASE obtained in step 306 is smaller than the maximum injection amount QFULL obtained in step 306. If the basic injection amount QBASE is smaller than the maximum injection amount QFULL, in step 308, the basic injection amount QBASE is set to the final injection amount QFIN. Subsequently, at step 309, an injection amount command value ANGSPV corresponding to the final injection amount QFIN is obtained. In step 310, the obtained injection amount command value ANGSPV is output, that is, the drive control of the electromagnetic spill valve 23 is performed based on the injection amount command value ANGSPV corresponding to the basic injection amount QBASE, and the subsequent processing is temporarily terminated. I do.

On the other hand, if the basic injection amount QBASE is not smaller than the maximum injection amount QFULL in step 307, the maximum injection amount QFULL is set to the final injection amount QFIN in step 311. Subsequently, at step 309, the injection amount command value ANGS corresponding to the final injection amount QFIN.
Find PV. And finally, in step 310,
The calculated injection amount command value ANGSPV is output, that is, the drive control of the electromagnetic spill valve 23 is performed based on the injection command value ANGSPV corresponding to the maximum injection amount QFULL, and the subsequent processing is temporarily terminated.

As described above, the fuel injection amount control of the diesel engine 2 is executed. As described above, in this embodiment, among the correction coefficients used for calculating the maximum injection amount QFULL, the fuel temperature correction coefficient KTF that reflects the fuel temperature TF having a large temporal variation is determined by the fuel temperature sensor 36. Relatively fast 1 based on the exact fuel temperature TF detected directly at
It is calculated for each control cycle of sec. On the other hand, the integral control correction coefficient KNFI learned during the ISC control by reflecting the secular change and the fuel property of the fuel injection pump 1 having a small temporal variation is slowly increased on the order of one day or two days. The learning is updated at the specified speed. Therefore, when learning the integral control correction coefficient KNFI from which the influence of the fuel temperature TF has been eliminated, the influence of load fluctuations caused by devices linked to the diesel engine 2, for example, an air conditioner or an electric system, is very small.

Therefore, when calculating the maximum injection amount QFULL, correction can be performed based on the proper integral control correction coefficient KNFI learned by taking only the influence of the aging of the fuel injection pump 1 and the like, and The correction can be performed based on the appropriate fuel temperature correction coefficient KTF taking only the influence of the fluctuation of the temperature TF into account. Further, in the conventional example, it was necessary to set the correction amount of the ISC control to be small in anticipation of the erroneous correction. However, in this embodiment, the possibility of the erroneous correction in the fuel injection amount control is reduced. It is not necessary to set the fuel temperature correction coefficient KTF and the integral control correction coefficient KNFI smaller than necessary, and it is possible to set them to practical values.

As a result, the correction of the fuel injection amount with respect to the aging and the change in the fuel temperature TF can be performed appropriately and accurately by eliminating the influence of the temporary load change caused by the air conditioner or the electric system. The reliability of the injection amount control can be improved. In other words, according to the fuel injection amount control device of this embodiment, even if the fuel temperature TF changes after a long time after the start of the diesel engine 2, the fuel temperature TF and the engine speed NE change as described above. Corresponding fuel temperature correction coefficient K
TF is suitably calculated. That is, when the fuel temperature TF is low, the maximum injection amount QFULL is corrected to be small, and the fuel temperature T
When F is large, the maximum injection amount QFULL is largely corrected. Therefore, the amount of fuel leakage from the gap between the plunger 12 and the cylinder 14 of the fuel injection pump 1 is taken into account,
The amount of fuel actually injected is sufficient for the diesel engine 2, and the fuel efficiency of the diesel engine 2 can be improved, smoke and the like can be prevented, and stable output characteristics can be maintained. Can be.

In addition, according to the fuel injection amount control device of this embodiment, the integral control correction coefficient KNFI which eliminates the influence of the fuel temperature TF according to the learning value NFIG and the engine speed NE as described above is preferable. Is calculated. That is, when the learning value NFIG is small, the maximum injection amount QFULL is corrected to be small, and when the learning value NFIG is large, the maximum injection amount QFULL is corrected.
LL is greatly corrected. Therefore, it is possible to perform high-precision and good fuel injection control in response to the change characteristics of the injection amount due to adjustment variations and individual differences that differ from one fuel injection pump 1 to another, and its aging. Furthermore, in this embodiment, since the correction is performed by the intake pressure correction coefficient K2 corresponding to the supercharging pressure PiM, more accurate fuel injection control can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, and may be carried out as follows, with a part of the configuration being appropriately changed without departing from the spirit of the invention. (1) In the above embodiment, the fuel temperature correction coefficient KTF corresponding to the fuel temperature TF and the integral control correction coefficient KNFI excluding the influence of the fuel temperature TF are obtained, and the basic maximum injection amount QSPF0 and the maximum injection increase amount are obtained. Although the final maximum injection amount QFULL is determined by multiplying QSPF1 etc., the fuel temperature correction injection amount based on the characteristic of the fuel temperature TF and the integral control correction injection amount excluding the effect of the fuel temperature TF are respectively determined. Then, these may be added to the basic maximum injection amount to determine the final maximum injection amount.

(2) When determining from the two-dimensional map the fuel temperature correction coefficient KTF corresponding to the fuel temperature TF and the integral control correction coefficient KNFI excluding the influence of the fuel temperature TF, for example, for each of the correction coefficients KTF and KNFI, If two or more values are obtained and the correction coefficients KTF and KNFI are determined from their average values, the resolution of each of the correction coefficients KTF and KNFI is improved to perform more accurate fuel injection amount control. be able to.

(3) In the above embodiment, the diesel engine 2 having the turbocharger 48 as the supercharger is embodied. However, the diesel engine with the supercharger as the supercharger or the supercharger is provided. Not embodied in diesel engines.

[0057]

As described above in detail, according to the present invention, the fuel temperature correction value is calculated based on the fuel temperature, while the fuel temperature correction value is actually supplied to the diesel engine in a predetermined stable operation state. The non-fuel temperature correction value is learned and calculated at a slow speed based on the non-fuel temperature change characteristic that excludes the influence of the fuel temperature from the change characteristic of the operating state amount caused by the fuel amount to be calculated. The fuel injection amount in each operating state is corrected and calculated based on the fuel temperature correction value. For this reason, it is possible to compensate for fluctuations in the injection amount due to aging of the fuel injection pump and diesel engine and changes in the fuel temperature without being affected by temporary load fluctuations caused by an air conditioner or electric system linked to the diesel engine. In this way, the fuel injection amount can be appropriately corrected, and the fuel injection of the most desirable amount can be always performed in each operation state of the diesel engine to improve the fuel efficiency of the diesel engine and maintain stable output characteristics. And the occurrence of smoke can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram showing a fuel injection amount control device for a diesel engine according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating a distribution type fuel injection pump according to one embodiment.

FIG. 4 is a block diagram illustrating a configuration of an ECU according to one embodiment.

FIG. 5 is a flowchart illustrating an integral control amount calculation routine executed by an ECU according to one embodiment.

FIG. 6 is a map in which an integral correction amount for an absolute value of a difference between an engine speed and a target speed in one embodiment is predetermined.

FIG. 7 is a flowchart illustrating a routine for calculating a fuel temperature correction coefficient and an integral control correction coefficient executed by an ECU according to one embodiment.

FIG. 8 is a two-dimensional map in which a relationship among an engine speed, a fuel temperature, and a fuel temperature correction coefficient in one embodiment is determined in advance.

FIG. 9 is a two-dimensional map in which a relationship among an engine speed, a learning value, and an integral control correction coefficient in one embodiment is determined in advance.

FIG. 10 is a flowchart illustrating a main routine of a fuel injection amount control process executed by an ECU according to one embodiment.

FIG. 11 is a map in which a basic maximum injection amount with respect to an engine speed in one embodiment is determined in advance.

FIG. 12 is a map in which a maximum injection increase with respect to an engine speed in one embodiment is determined in advance.

FIG. 13 is a map in which an intake pressure correction coefficient for a supercharging pressure is determined in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump as fuel injection means, 2 ... Diesel engine, 35 ... Rotation speed sensor, 36 ... Fuel temperature sensor as fuel temperature detection means, 72 ... Intake air temperature sensor, 73
... Accelerator opening degree sensor, 74 ... Intake pressure sensor, 75 ... Water temperature sensor, 76 ... Crank angle sensor, 77 ... Vehicle speed sensor (35, 72 to 77 constitute driving state detecting means), 71 ... ECU (fuel) Injection amount calculation means, fuel injection control means, fuel temperature correction value calculation means, change characteristic calculation means,
Non-fuel temperature change characteristic calculating means, non-fuel temperature correction value calculating means, and fuel injection amount correction calculating means).

Claims (1)

(57) [Claims] 1. A fuel injection means for injecting fuel into a diesel engine, an operation state detection means for detecting an operation state of the diesel engine, and an injection to the diesel engine based on a detection result of the operation state detection means. A fuel injection amount control device for a diesel engine, comprising: a fuel injection amount calculating unit that calculates a fuel injection amount; and a fuel injection control unit that drives and controls the fuel injection unit based on a calculation result of the fuel injection amount calculating unit. A fuel temperature detection unit for detecting a temperature of fuel injected from the fuel injection unit to the diesel engine, and a fuel temperature correction value for correcting the fuel injection amount based on a detection result of the fuel temperature detection unit. The diesel engine is operated based on the fuel temperature correction value calculating means for calculating and the detection result of the operating state detecting means. A change characteristic calculating means for calculating a change characteristic of an operation state quantity caused by an amount of fuel actually supplied to the diesel engine in a constant stable operation state; a calculation result of the change characteristic calculation means; A non-fuel temperature change characteristic calculating means for calculating a non-fuel temperature change characteristic excluding the influence of the fuel temperature from the change characteristic of the operating state quantity based on a detection result of the detecting means; and the non-fuel temperature change characteristic calculating means Non-fuel temperature correction value calculation for learning and calculating a non-fuel temperature correction value for correcting the fuel injection amount at a slow speed capable of eliminating load fluctuations caused by equipment linked to the diesel engine based on the calculation result of Means, and the fuel injection amount calculating means calculates the fuel injection amount based on the calculation result of the non-fuel temperature correction value calculating means and the calculation result of the fuel temperature correction value calculating means. Fuel injection quantity control device for a diesel engine, characterized in that the fuel injection quantity and a fuel injection amount correction calculation means for correcting operation that.