JPH06249023A - Injection quantity control device for diesel engine - Google Patents

Abstract

PURPOSE:To correct a fuel injection quantity suitably at the time of start and block generarion of smoke and failure of start at the time of start certainly. CONSTITUTION:ECU 71 takes an injection quantity at the time of start before correction as an injection quantity at the time of start after correction without correcting the injection quantity at the time of start if cooling water temperature detected by a water temperature sensor is not more than 60 deg.C that is, an engine 2 is in its cooled state a lapse of time after the preceding engine stop the ECU 71 calculates an injection quantity after correction, by multiplying the injection quantity at the time of start before correction by an injection quantity correction coefficient found out based on learnt value calculated at the time of the last engine operation if cooling water temperature is more than 60 deg.C, that is, the engine 2 is in its hot state not so much lapse of time after the stop of the engine. Therefore, the injection quantity at the time of start is always controlled adequately depending on the level of cooling water temperature at the time of engine start.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for a diesel engine applied to, for example, an automobile.

[0002]

2. Description of the Related Art Conventionally, in order to improve fuel efficiency of a diesel engine, maintain preferable output characteristics, prevent smoke, and the like, various types of fuel have been injected from an injection pump to inject a required amount of fuel according to various operating conditions. Fuel injection amount control is being performed.

By the way, the light oil used as a fuel in a diesel engine has the property that its characteristics change depending on the temperature. That is, as the fuel temperature rises, the kinematic viscosity decreases and the fluidity of the fuel rises. On the contrary, as the fuel temperature decreases, the kinematic viscosity increases and the fluidity of the fuel decreases. Therefore, the change in the fuel property due to the change in the fuel temperature causes the fuel to leak from the gap of the high-pressure fuel pumping system of the fuel injection pump to the pump low-pressure chamber side, which causes an error in the actual injection amount. There was a problem. Also, this injection amount error due to the fuel temperature is
Changes in operating conditions such as engine speed and engine load,
It also fluctuated due to changes over time in the engine.

Therefore, for example, in the technique disclosed in Japanese Patent Laid-Open No. 1-294938, in order to compensate the error of the injection amount due to the change of the fuel temperature (fuel fluidity) or the operating state, the following is performed. Fuel injection amount control is being performed. That is, in a stable operating state during idle speed control (ISC), the change characteristic of the operating state amount due to the amount of fuel actually supplied to the combustion chamber is calculated as the ISC control amount. Then, the correction amount of the maximum fuel injection amount is calculated from the learned value of the ISC control amount and the coefficient obtained based on the engine speed assuming the fuel injection amount error. Then, based on the calculated correction amount, the maximum injection amount in the traveling state is corrected at any time.
Therefore, in this conventional technique, the maximum injection amount can be suitably corrected according to each operating state regardless of the change in the fuel property, and the most desirable required injection amount for the diesel engine can be actually controlled for injection. You can

[0005]

However, the technique disclosed in the above-mentioned prior art is for correcting and controlling the maximum injection amount during normal operation of the engine, and is not for correcting and controlling the injection amount during starting as well. That is, the learned value of the ISC control amount is updated at any time when the engine is idle and is stored and held in the memory, and when the engine is stopped,
The finally calculated learning value is stored and held in the memory. Therefore, unlike normal engine operation,
It is not appropriate to use the learning value calculated during the last engine operation as the correction amount of the fuel injection amount as it is at the time of starting when the engine is in a cold state because an error is likely to occur in the correction.

Therefore, in the above-mentioned prior art, the injection amount at the time of starting is not corrected, and there is a possibility that the injection amount at the time of starting may deviate from the preferable injection amount. Therefore, at the time of starting, the fuel injection amount may become unnecessarily large and waste of fuel or smoke may occur, or the fuel injection amount may be insufficient and start failure may occur. .

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to be able to suitably correct the fuel injection amount at the time of starting, and to generate smoke and start failure at the time of starting. It is an object of the present invention to provide a fuel injection amount control device for a diesel engine that can reliably prevent the above.

[0008]

In order to achieve the above object, in the present invention, as shown in FIG. 1, fuel injection means M2 for injecting fuel into a diesel engine M1, and
An operating state detecting means M3 for detecting an operating state including the rotational speed of the diesel engine M1 and a fuel injection amount at the time of starting to be injected into the diesel engine M1 are calculated based on the detection result of the operating state detecting means M3. Starting injection amount calculating means M4 and the starting injection amount calculating means M4
In a fuel injection amount control device for a diesel engine, which comprises a fuel injection control means M5 for driving and controlling the fuel injection means M2 based on the calculation result of the above, the diesel engine based on the detection result of the operating state detection means M3 Change characteristic calculating means M6 for calculating change characteristics of the operating state amount due to the amount of fuel actually supplied to the diesel engine M1 when M1 is in a predetermined stable operating state,
Based on the calculation result of the change characteristic calculation unit M6, a correction value calculation unit M7 for learning and calculating a correction value for correcting the fuel injection amount, and the start-time injection amount based on the calculation result of the correction value calculation unit M7. Injection amount correction calculation unit M for correcting and calculating the fuel injection amount at startup calculated by the calculation unit M4
8, a cooling liquid temperature detecting means M9 for detecting the temperature of the cooling liquid for cooling the diesel engine M1, and a correction value calculated by the correction value calculating means M7 are detected by the cooling liquid temperature detecting means M9. A correction setting means M10 for setting a predetermined value according to the result is provided.

[0009]

According to the above construction, as shown in FIG. 1, for example, when the diesel engine M1 is started, the operating state detecting means M3 detects the operating state of the diesel engine M1. Further, based on the detection result, the starting injection amount calculating means M4 calculates the starting fuel injection amount to be injected into the diesel engine M1.

The change characteristic calculating means M6 is based on the detection result of the operating state detecting means M3, and the diesel engine M
A change characteristic of the operating state amount due to the amount of fuel actually supplied to the diesel engine M1 when 1 is a predetermined stable operating state, for example, an idle operating state is calculated. Then, based on the calculation result, the correction value calculation means M7 learns and calculates the correction value for correcting the fuel injection amount.

Further, the injection amount correction calculation means M8 corrects and calculates the fuel injection amount at the time of start calculated by the start time injection amount calculation means M4 based on the calculation result of the correction value calculation means M7. At this time, the coolant temperature detecting means M9 detects the temperature of the coolant for cooling the diesel engine M1. Then, the correction setting means M10 sets the correction value calculated by the correction value calculating means M7 to a predetermined value according to the detection result of the coolant temperature detection means M9.

Therefore, the injection amount correction calculating means M8 corrects and calculates the fuel injection amount at the time of starting based on the correction value set by the correction setting means M10. Then, the fuel injection control unit M5 drives and controls the fuel injection unit M2 based on the corrected and calculated fuel injection amount at the time of starting, and the fuel injection amount to the diesel engine M1 is controlled.

That is, the correction value learned and calculated by the correction value calculation means M7 is calculated when the diesel engine M1 is in a predetermined stable operation state such as an idle operation state. Therefore, the diesel engine M1
When the engine is started, the fuel injection amount is corrected based on the correction value learned and calculated during the previous engine operation.

At this time, when the coolant temperature is low, that is, when the diesel engine M1 is in a cold state after a lapse of time since the last engine stop, the kinematic viscosity of the fuel increases and the fluidity decreases. Therefore, the fuel injection amount error becomes small, and the actual fuel injection amount does not decrease so much. Therefore, in such a case, for example, the correction value learned and calculated during the previous engine operation is set to a small value or not present to prevent the fuel injection amount from being increased and corrected. This prevents waste of fuel and generation of smoke at the time of starting.

Further, when the coolant temperature is high, that is, when the diesel engine M1 is in a warm state for a short time since the last engine stop, the kinematic viscosity of the fuel is lowered and the fluidity is deteriorated. Since the fuel injection amount increases, the error of the fuel injection amount increases, and the actual fuel injection amount decreases. Therefore, in such a case, for example, the correction value learned and calculated during the previous engine operation is set to the same value, and the fuel injection amount is increased and corrected. As a result, it is possible to prevent the occurrence of a starting failure at the time of starting.

As described above, depending on whether the coolant temperature is high or low,
Since the correction value learned and calculated during the previous engine operation can be set to the optimum value, the starting injection amount can be properly corrected and calculated, and the appropriate starting injection amount control can be performed at all times. .

[0017]

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 the drawings.

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 a distribution type fuel injection pump 1 constituting its fuel injection means. Is. 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 fuel injection pump 1 is driven by the rotation of the drive pulley 3, and the fuel is pressure-fed 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, 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 formed of 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, in this case, four cutting teeth are formed at equal angular intervals, and 14 projections (56 in total) are formed between each cutting tooth at equal angular intervals. There is. 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 attached along the circumference of the roller ring 9. 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 the coupling, the cam plate 8 rotates and engages with the cam roller 10 to reciprocate in the left-right direction in the figure by the same number as the number of cylinders. Driven. Also, the plunger 12 is reciprocally driven in the same direction while rotating with the reciprocating motion. That is,
When the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, the plunger 12 is moved forward (lifted), and conversely, when the cam face 8a rides on the cam roller 10, the plunger 12 is moved back.

The plunger 12 is fitted in 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. In addition, the outer periphery of the tip end 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 in the.

Then, the drive shaft 5 is rotated and the fuel feed pump 6 is driven, so that 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 to 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, the fuel is pressure-fed and injected from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder.

The pump housing 13 has a fuel overflow spill passage 22 for communicating the high pressure chamber 15 and the fuel chamber 21.
Are formed. A known electromagnetic spill valve 23 for injection adjustment is provided in the middle of the spill passage 22.
This electromagnetic spill valve 23 is a normally open type valve and has a coil 24
Is de-energized (off), the valve body 25 is opened and the fuel in the high pressure chamber 15 overflows into 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 energizing time of the electromagnetic spill valve 23, the valve 23 is controlled to be closed / opened, and the fuel overflow control from the high pressure chamber 15 to the fuel chamber 21 is performed. 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. Further, during the forward movement of the plunger 12, by controlling the closing / opening timing of the electromagnetic spill valve 23, the fuel injection amount from the fuel injection nozzle 4 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. This timer device 26
Controls the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5 to control 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 has 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. Then, the timer piston 28 moves the roller ring 9 via the slide pin 32.
It is connected to the.

In the pressure 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 equilibrium relationship 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 position of the roller 1 is determined via the cam plate 8.
2 reciprocating timing 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 with each other by the communication passage 34, and the timing control valve 33 is provided in the middle of the communication passage 34. The timing control valve 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 valve 33.
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.

A rotation speed sensor 35 composed of an electromagnetic pickup coil is mounted above the roller ring 9 so as to face the outer peripheral surface of the pulsar 7. This rotation speed sensor 35
When the protrusions and the like of the pulsar 7 cross, the passages are detected and a timing signal (engine rotation pulse) corresponding to the engine speed NE is output. 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,
Each of the main combustion chambers 44 is connected to an auxiliary combustion chamber 45 that is also provided corresponding to each cylinder. Then, the fuel injected from each fuel injection nozzle 4 is supplied to each auxiliary combustion chamber 45. A well-known glow plug 46 as a start-up assisting device is attached to each sub-combustion chamber 45.

The diesel engine 2 is provided with an intake pipe 47 and an exhaust pipe 50, the intake pipe 47 is provided with a copressor 49 of a turbocharger 48 constituting a supercharger, and the exhaust pipe 50 is provided with a turbocharger. 48
A turbine 51 of is provided. In addition, the exhaust pipe 50 has a wastegate valve 5 for adjusting the boost pressure PiM.
Two are provided. As is well known, the turbocharger 48 uses the energy of the exhaust gas to rotate the turbine 51 and the compressor 49 coaxially with the turbine 51 to rotate the intake air. As a result, high-density air 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 5
A recirculation pipe 54 is provided for recirculating a part of the exhaust gas in 0 to the intake port 53 of the intake pipe 47. An exhaust gas recirculation valve (EGR valve) 55 for adjusting the recirculation amount of exhaust gas is provided in the middle of the recirculation pipe 54. The EGR valve 55 is opened / closed by controlling 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.

In addition, the diesel engine 2 is provided with a starter 64 for imparting a rotational force by cranking at the time of starting, and the starter 64 is provided with a starter switch 65 for detecting and outputting its on / off operation. It is provided. As is well known, the starter 64 is turned on / off by operating an ignition switch (not shown). While the ignition switch is being operated, the starter 64 is turned on and the starter signal 65 outputs the starter signal ST. It is supposed to be done.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above.
3, the timing control valve 33, the glow plug 46, and the VSVs 56, 61, 62 each include a starting injection amount calculation means, a fuel injection control means, a change characteristic calculation means, a correction value calculation means, an injection amount correction calculation means, and a correction setting. An electronic control unit (hereinafter simply referred to as "ECU") 71 that constitutes the means.
, And the drive timings thereof are controlled by the ECU 71.

As the sensors constituting the operating state detecting means, the following various sensors are provided in addition to the rotation speed sensor 35 and the starter switch 65. That is, the intake pipe 47 has an intake air temperature T near the air cleaner 66.
An intake air temperature sensor 72 that detects HA is provided.
Further, an accelerator opening sensor 73 for detecting an 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 for detecting the intake air pressure after supercharging by the turbocharger 48, that is, the supercharging pressure PiM, is provided near the intake port 53. Further, a water temperature sensor 75 is provided as a coolant temperature detecting means for detecting the coolant temperature THW of the diesel engine 2.
Further, the rotation reference position of the crankshaft 40 of the diesel engine 2, for example, the crankshaft 40 with respect to the top dead center of the specific cylinder.
A crank angle sensor 76 for detecting the rotational position of the is provided. Furthermore, for the transmission not shown,
A vehicle speed sensor 77 is provided which detects the vehicle speed (vehicle speed) SP by turning on / off the reed switch 77b by a magnet 77a rotated by the rotation of the gear.

The above-mentioned sensors 72 to 77 are respectively connected to the ECU 71, and the rotation speed sensor 3 is connected.
5 and the starter switch 65 are connected. Also, E
The CU 71 suitably controls the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSV 56, 61, 62 and the like based on the signals output from the sensors 35, 72 to 77 and the starter switch 65.

Next, the configuration of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 is 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.

At the input port 85, the intake temperature sensor 72, the accelerator opening sensor 73, the intake pressure sensor 74,
The water temperature sensor 75 and the starter switch 65 are used for the buffers 88, 89, 90, 91, 92 and the multiplexer 93.
And an A / D converter 94. Similarly, the input port 85 is connected to the rotation speed sensor 35,
The crank angle sensor 76 and the vehicle speed sensor 77 are connected via a waveform shaping circuit 95. And the CPU 81
Is each sensor 35, 7 input via the input port 85.
2 to 77 and the detection signals of the starter switch 65 and the like are read as input values. The output port 86 is connected to the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSV 56, 61, 62, etc. via the drive circuits 96, 97, 98, 99, 100, 101.

Then, the CPU 81 controls the sensors 35 and 72.
~ 77 and the input value read from the starter switch 65, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46 and the VSV 56, 61,
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 the flowcharts shown in FIGS. 5, 7 to 9 and the maps shown in FIGS. 6, 10 and 11.

First, the flow chart shown in FIG.
It is a routine for calculating an integral control amount NFI used for idle speed control (ISC) control in the idle stable state of the diesel engine 2 among the processes executed by U71. It should be noted that this routine is executed during the previous engine operation.

When the processing shifts to this routine, first, at step 101, the accelerator opening ACCP, the vehicle speed SP and the engine speed NE are based on the detected values of the accelerator opening sensor 73, the vehicle speed sensor 77, the rotation speed sensor 35 and the like. Respectively.

Next, at step 102, it is judged if the engine 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.

Then, if the idle stable state is not established, the process is temporarily terminated. If the engine is in the idling stable state, it is determined in step 103 whether the actual engine speed NE previously read after the diesel engine 2 is started is equal to the target engine speed NF in the idling stable state. . Then, when the actual engine speed NE is equal to the target speed NF, the processing is temporarily terminated as it is. Also, the actual engine speed N
If E is not equal to the target speed NF, step 1
Move to 04.

At 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 engine speed NF. This integral correction amount ΔNFI is obtained by referring to a predetermined map as shown in FIG.

Then, in step 105, it is determined whether the actual engine speed NE is higher than the target speed NF. Then, when the actual engine speed NE is higher than the target speed NF, in step 106, the integral control amount NF obtained in the previous control cycle is calculated.
The result obtained by subtracting the integral correction amount ΔNFI from I0 is set as the current integral control amount NFI, and the process is temporarily terminated.
If the actual engine speed NE is not higher than the target engine speed NF, the result obtained by adding the integral correction amount ΔNFI to the integral control amount NFI0 obtained in the previous control cycle is calculated in step 107. The integral control amount NFI is set, and the process ends.

As described above, the integral control amount NFI used for the ISC control is calculated. FIG. 7 shows an injection amount correction learning value NF used to calculate the fuel injection amount in the idle stable state of the diesel engine 2.
This is a routine for calculating IGQ. It should be noted that this routine is also executed in the previous engine operation, like the routine of FIG.

When the processing shifts to this routine, first in step 201, the cooling water temperature THW is read based on the detection value of the water temperature sensor 75, and the battery voltage VB of the battery (not shown) is also read based on the detection value of the voltmeter (not shown). . Subsequently, in step 202, it is determined whether or not the idle stable state is established.

Then, when the idle stable state is not established, the processing is temporarily terminated as it is. If it is in the idle stable state, in step 203, it is judged whether or not the read cooling water temperature THW is a high temperature of “60 ° C.” or higher. The process is terminated as it is. When the value of the cooling water temperature THW is “60 ° C.” or more, the value of the battery voltage VB read in step 204 is “12.4.
It is determined whether or not it is V or more. Then, when the value of the battery voltage VB is not "12.4 V" or more, the processing is temporarily terminated as it is. If the value of the battery voltage VB is "12.4 V" or more, it is determined that the learning condition for the injection amount correction learning value NFIGQ (unit is "rpm") is satisfied, and the step 205 is performed. Move to.

In step 205, the learning value NFIGQ0 (unit is "rpm") in the previous control cycle is
It is determined whether or not it is larger than the integral control amount NFI obtained by the routine of FIG. If the learning value NFIGQ0 is larger than the integral control amount NFI, step 206
In, the result of subtracting "3.0 (rpm)" from the learning value NFIGQ0 in the previous control cycle is set as the updated learning value NFIGQ, and the process is temporarily terminated.

On the other hand, in step 205, the learning value N
If FIGQ0 is not larger than the integrated control amount NFI, in step 207, the result obtained by adding "1.0 (rpm)" to the learning value NFIGQ0 in the previous control cycle is set as the updated learning value NFIGQ. , The process is once ended.

In this way, the calculation of the injection amount correction learning value NFIGQ used for calculating the fuel injection amount is executed, and the data of this learning value NFIGQ is stored in the backup RAM.
It is stored and held in 84. Therefore, when the engine 2 is stopped, the finally calculated learning value NFIGQ is stored and held in the backup RAM 84.

On the other hand, the flow chart shown in FIG.
Among the processes executed by U71, the main routine for controlling the fuel injection amount at the time of starting the diesel engine 2 is shown.

When the processing shifts to this routine, first, at step 301, the engine speed is determined based on the detected values of the rotation speed sensor 35, accelerator opening sensor 73, intake pressure sensor 74, water temperature sensor 75 and starter switch 65. NE, accelerator opening ACCP, supercharging pressure PiM, cooling water temperature THW, and starter signal ST are read.

Next, at step 302, the basic fuel injection amount QBASE0 is calculated from the read engine speed NE, accelerator opening ACCP, and the like. The calculation of the basic injection amount QBASE0 is performed with reference to a predetermined map (not shown) having the engine speed NE and the accelerator opening ACCP as parameters.

Next, at step 303, it is judged whether or not the value of the cooling water temperature THW previously read is “10 ° C.” or more. The value of the cooling water temperature THW is "10.
If it is equal to or higher than “° C.”, in step 304, based on the starter operation time CSTA, which is the elapsed time from the start of cranking, the engine speed NE, and the like, the uncorrected fuel amount is corrected according to a predetermined calculation formula. The injection amount QSTA0 at start is calculated. That is, when the cooling water temperature THW is not extremely low, it is determined that the engine startability is relatively good, and in order to prevent waste of fuel and smoke, engine speed NE by cranking and starter operating time CSTA, etc. Based on, the minimum fuel injection amount is set. The starter operating time CSTA is calculated by measuring the ON time of the starter 64 based on the previously read starter signal ST.

On the other hand, when the value of the cooling water temperature THW is not "10 ° C." or more in step 303, in step 305, based on the accelerator opening ACCP, the starting pseudo accelerator opening ACSTA, the engine speed NE, etc., The pre-correction fuel injection amount at start-up QSTA0 is calculated according to a predetermined calculation formula. That is, when the cooling water temperature THW is extremely low, it is determined that the engine startability is not good, and in order to improve the startability, the fuel injection amount corrected for increase is set according to the engine operating state at that time. . The starting pseudo accelerator opening ACSTA is obtained based on the cooling water temperature THW by referring to a predetermined map (not shown).

Next, at step 306, it is judged if the value of the cooling water temperature THW is "60 ° C." or higher. Then, when the value of the cooling water temperature THW is not equal to or higher than "60 ° C.", that is, when the engine 2 is in a cold state after a lapse of time since the last engine stop, in step 307, the calculated correction is performed. The previous starting injection amount QSTA0 is not corrected and is directly used as the corrected starting injection amount QSTA.

On the other hand, in step 306, when the value of the cooling water temperature THW is "60 ° C." or more, that is, the engine 2 is not so much time has elapsed since the engine was stopped.
If is in a warm state, the injection amount correction coefficient MQSG is calculated in step 308. The flowchart shown in FIG. 9 shows a routine for calculating the injection amount correction coefficient MQSG in step 308.

When the processing shifts to this routine, first, at step 309, the rotational speed correction coefficient MQSGH is obtained from the previously read engine rotational speed NE. This rotation speed correction coefficient MQSGH is obtained by referring to a predetermined map as shown in FIG. Next, in step 310, the integral control correction coefficient MQS is calculated based on the injection amount correction learning value NFIGQ calculated during the previous engine operation and stored and retained in the backup RAM 84.
Find the GN. This integral control correction coefficient MQSGN is obtained by referring to a predetermined map as shown in FIG.

Then, in step 311, the injection amount correction coefficient MQSG is calculated from the obtained rotational speed correction coefficient MQSGH, the integral control correction coefficient MQSGN, and the injection value correction learning value NFIGQ. This calculation is performed according to the following equation (1).

MQSG = 1 + NFIGQ × MQSGH × MQSGN (1) Then, when the injection amount correction coefficient MQSG is calculated, the process is temporarily terminated.

Returning to the main routine of FIG. 8, step 3
In 12, the pre-correction starting injection amount Q before correction
In STA0, the injection amount correction coefficient M calculated in the routine of FIG.
The corrected starting injection amount QSTA is calculated by multiplying QSG.

Then, in step 313, it is determined whether or not the engine is starting based on the starter signal ST and the engine speed NE that have been read in advance. If it is during the start, in step 314, the value of the corrected start-time injection amount QSTA previously obtained and the step 3
The value of the basic injection amount QBASE0 obtained in 02 is compared, and the smaller value is set as the basic injection amount QBASE of this time. If the engine is not started, the value of the basic injection amount QBASE0 obtained in step 302 is set as the current basic injection amount QBASE in step 315.

Next, at step 316, the maximum injection amount QFULL is calculated. The calculation of this maximum injection amount QFULL is
This is performed with reference to a predetermined map (not shown) having the engine speed NE, the supercharging pressure PiM and the like as parameters. Then, in step 317, the previous step 3
The maximum injection amount QFULL obtained in 16 and step 3
14 or the basic injection amount QBA obtained in step 315
Compare the SE value and use the smaller value to determine the final injection amount Q
Set as FIN.

Subsequently, at step 318, the injection amount command value TSP corresponding to the final injection amount QFIN is obtained. Then, in step 319, the obtained injection amount command value TSP is output. That is, the previous step 3
The maximum injection quantity QFULL as the final injection quantity QFIN in 17
If set, in step 319, the electromagnetic spill valve 23 is drive-controlled based on the injection amount command value TSP corresponding to the maximum injection amount QFULL, and the subsequent processing is temporarily ended.

On the other hand, when the basic injection amount QBASE is set as the final injection amount QFIN in the previous step 317, the electromagnetic spill valve 23 is driven based on the injection command value TSP corresponding to the basic injection amount QBASE in step 319. The control is performed and the subsequent processing is once ended.

As described above, the fuel injection amount control at the time of starting the diesel engine 2 is executed. As described above, in this embodiment, the value of the cooling water temperature THW is “60”.
If the temperature is not higher than "° C", that is, if the engine 2 is in a cold state after a lapse of time since the last engine stop, the pre-correction start-up injection amount QSTA0 is not corrected and the start-up is performed after the correction. The injection quantity is QSTA. on the other hand,
When the value of the cooling water temperature THW is “60 ° C.” or more, that is, when the engine 2 is in a warm state after not much time has passed since the engine was stopped, the pre-correction starting injection amount QSTA0 is The corrected injection quantity at start QSTA is calculated by multiplying the injection quantity correction coefficient MQSG calculated based on the learned value NFIGQ.

That is, when the engine 2 is in a cold state, the kinematic viscosity of the fuel increases and the fluidity decreases. Therefore, the amount of fuel leakage from the gap between the plunger 12 and the cylinder 14 of the fuel injection pump 1 is reduced, the fuel injection amount error is reduced, and the actual fuel injection amount does not decrease so much. Therefore, in such a case, the learning value NF calculated during the last engine operation
Injection amount correction coefficient M as a correction value obtained based on IGQ
The QSG prevents the pre-correction start-up injection amount QSTA0 from being corrected. In other words, the injection amount correction coefficient MQ
The SG is set as not present to prevent the startup injection amount QSTA0 from being increased and corrected. As a result, the waste of fuel and the occurrence of smoke at the time of starting can be prevented and reliably prevented.

When the engine is in a warm state, the kinematic viscosity of the fuel decreases and the fluidity increases, so
The fuel leakage amount increases, the fuel injection amount error increases, and the actual fuel injection amount decreases. Therefore, in such a case, in consideration of the injection amount error, the start-up injection amount Q before correction is determined by the injection amount correction coefficient MQSG obtained based on the learning value NFIGQ calculated during the previous engine operation.
I am trying to correct STA0. In other words, the injection amount correction coefficient MQSG is set to the value as it is, and the startup injection amount QSTA0 is increased and corrected. As a result, it is possible to reliably prevent the occurrence of a start failure at the start.

In this way, the learning value NFIGQ calculated during the previous engine operation according to the level of the cooling water temperature THW.
It is possible to set the injection amount correction coefficient MQSG obtained on the basis of the optimum value. Therefore, the pre-correction start-up injection amount QSTA0 is properly corrected and calculated to correct the start-up injection amount QSTA0.
Can be STA, cooling water temperature THW at start
It is possible to always perform appropriate start-time injection amount control in accordance with the level of.

Further, in this embodiment, since the injection amount correction due to the change in the fuel property can be performed without using a special sensor such as the fuel temperature sensor, the fuel injection amount control device is inexpensive.

The present invention is not limited to the above-described embodiment, but may be implemented as follows with a part of the configuration appropriately modified without departing from the spirit of the invention. (1) In the above embodiment, when controlling the fuel injection amount at the start,
Although it was determined whether the injection amount QSTA0 at start-up was corrected or not depending on the cooling water temperature THW, the injection amount correction coefficient MQS
At the time of calculating G, the value of the injection amount correction coefficient MQSG may be set to a predetermined value according to the level of the cooling water temperature THW. That is, when the cooling water temperature THW is “60 ° C.” or more, the value of the injection amount correction coefficient MQSG is left as it is, and when it is not “60 ° C.” or more, the injection amount correction coefficient M
Set the value of QSG to 1. Then, the value of the injection amount correction coefficient MQSG set in this way is used as the cooling water temperature THW.
Irrespective of whether the value is high or low, the starting injection amount QSTA0 before correction is multiplied. At this time, the value of the injection amount correction coefficient MQSG may be set to a value larger than 1 even when the cooling water temperature THW is not “60 ° C.” or higher. This allows the engine 2
Even when the engine is in a cold state, the injection amount correction amount can be reflected in the corrected starting injection amount QSTA.

(2) In the above embodiment, the injection amount QST at the time of starting
With or without correction of A0, the value of the cooling water temperature THW is "60".
It was judged based on whether or not it was above "℃", but change this to another temperature and set it.

(3) In the above embodiment, the diesel engine 2 having the turbocharger 48 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.

[0078]

As described above in detail, according to the present invention, the temperature of the coolant is detected at the time of starting the engine, and the learning calculation is performed at the previous engine operation according to the detected temperature of the coolant. The correction value of the fuel injection amount thus set is set to a predetermined value. Therefore, it becomes possible to properly perform the correction calculation of the injection amount at the time of starting, and it is possible to always perform an appropriate control of the injection amount at the time of starting according to the coolant temperature at the time of starting, thereby generating or starting smoke. It has an excellent effect that it is possible to reliably prevent the occurrence of defects. Further, since no special sensor or the like is required, the device can be constructed at low cost.

[Brief description of 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 in one embodiment embodying the present invention.

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

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

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

FIG. 6 is a map in which an integral correction amount with respect to 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 learning value calculation routine for correcting the injection amount, which is executed by the ECU in the embodiment.

FIG. 8 is a flowchart illustrating a main routine of a fuel injection amount control process executed by an ECU in one embodiment.

FIG. 9 is a flowchart illustrating a routine for calculating an injection amount correction coefficient, which is performed in a main routine in one embodiment.

FIG. 10 is a map in which a rotation speed correction coefficient with respect to an engine rotation speed in one embodiment is predetermined.

FIG. 11 is a map in which an integral control correction coefficient for a learning value for injection amount correction in one embodiment is predetermined.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump as fuel injection means, 2 ... Diesel engine, 35 ... Rotation speed sensor, 65 ... Starter switch, 72 ... Intake temperature sensor, 73 ... Accelerator opening sensor, 74 ... Intake pressure sensor, 75 ... Coolant Water temperature sensor as temperature detecting means, 76 ... Crank angle sensor, 77 ... Vehicle speed sensor (35, 65, 72 to 77 constitute operating state detecting means), 71 ... ECU (starting injection amount calculating means, fuel (Injection control means, change characteristic calculation means, correction value calculation means, injection amount correction calculation means, and correction setting means).

Claims (1)

[Claims] 1. A fuel injection means for injecting fuel into a diesel engine, an operating state detecting means for detecting an operating state including a rotational speed of the diesel engine, and the diesel engine based on a detection result of the operating state detecting means. A start-time injection amount calculation means for calculating the fuel injection amount at the start to be injected into the engine, and a fuel injection control means for drivingly controlling the fuel injection means based on the calculation result of the start-time injection amount calculation means. In a fuel injection amount control device for a diesel engine provided, based on the detection result of the operating state detection means, due to the amount of fuel actually supplied to the diesel engine when the diesel engine is in a predetermined stable operating state Change characteristic calculating means for calculating change characteristic of operating state quantity, and fuel injection based on the calculation result of the change characteristic calculating means Correction value calculation means for learning and calculating a correction value for correcting the fuel injection amount, and injection for correcting and calculating the fuel injection amount at the start time calculated by the start time injection amount calculation means based on the calculation result of the correction value calculation means. Amount correction calculation means, coolant temperature detection means for detecting the temperature of the coolant for cooling the diesel engine, correction value calculated by the correction value calculation means, the detection result of the coolant temperature detection means A fuel injection amount control device for a diesel engine, comprising: a correction setting unit that sets a predetermined value in accordance with the above.