JP2808921B2 - 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 amount control device for a diesel engine applied to, for example, an automobile, and more particularly to a fuel injection amount control device for controlling a fuel injection amount at the time of starting.

[0002]

2. Description of the Related Art Conventionally, in connection with control of the fuel injection amount of a diesel engine, it has been generally practiced to increase the fuel injection amount at the time of starting in order to improve the startability of the engine by cranking. . However, even if the fuel injection amount is increased uniformly, a suitable increase during cold start at extremely low temperature or the like, which is unfavorable for the engine, may be unnecessarily increased during warm start with high engine temperature. turn into. Therefore, not only wasted fuel is consumed, but also emission of black smoke, CO, HC, and the like in the exhaust gas is increased.

[0003] Therefore, for example, in the technology disclosed in Japanese Patent Application Laid-Open No. 57-65821, the engine temperature and the
It has been proposed to increase and correct the fuel injection amount based on the engine speed by cranking and the elapsed time from the start of cranking. Therefore, according to this technology,
The fuel injection increase correction is performed at the time of cold start or warm start based on the engine temperature, and the increase correction is performed according to the engine speed at that time, thereby reducing the amount of fuel injected wastefully. It was something that could be done.

[0004]

However, in the above-mentioned prior art, although the increase in the injection amount is corrected based on a correction coefficient corresponding to the engine temperature and the magnitude of the engine speed, the cranking starts. The correction coefficient according to the elapsed time from is set so as to decrease according to the time. Therefore, the increase correction amount of the injection amount according to the elapsed time from the start of cranking is reduced according to the elapsed time. Therefore, in the diesel engine to which the technique of the above-mentioned conventional publication is applied, it is only necessary that the friction loss is small and the increase in the rotation speed is good. Elapsed time from start is longer. And, since the increase correction amount of the injection amount decreases with the lapse of time from the start of cranking, the rotation speed of the diesel engine becomes more difficult to increase. as a result,
There has been a problem that the start-up time of the diesel engine is prolonged, and the fuel injection amount that is increased and corrected before the start is completed increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to minimize the amount of fuel injection that is increased and corrected by the time the start is completed. It is an object of the present invention to provide a diesel engine fuel injection amount control device capable of reducing the fuel consumption.

[0006]

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,
Operating state detecting means M3 for detecting an operating state including the number of revolutions of the diesel engine M1, and operating state detecting means M
3. A fuel injection amount calculating means M4 for calculating a fuel injection amount to be injected into the diesel engine M1 based on the detection result of No. 3.
And a fuel injection control means M5 for driving and controlling the fuel injection means M2 based on the calculation result of the fuel injection amount calculation means M4.
The cranking of the diesel engine M1 by the starter based on the detection result of the operating state detecting means M3
Starting cranking determining means M for determining the time
6 and the starting cranking determining means M6.
When it is determined that the engine is in the cranking state, a timer means M7 for counting the time elapsed from the start of cranking, and a fuel injection amount calculating means M4 when the timer result of the timer means 7 exceeds a predetermined reference time. And a fuel injection amount increase correction means M8 for increasing and correcting the calculation result of the fuel injection amount by the above.

[0007]

According to the above configuration, as shown in FIG. 1, when the diesel engine M1 is started by cranking by the starter , the starting cranking judging means M6 is based on the detection result of the operating state detecting means M3. Judge that. The clocking means M7 starts cranking at the time of starting.
When it is determined by the determining means M6 that the cranking is being performed, the elapsed time from the start of the cranking is counted. Further, the fuel injection amount calculation means M4 calculates the fuel injection amount to be injected into the diesel engine M1 based on the detection result of the operating state detection means M3, and based on the calculation result, the fuel injection control means M5 controls the fuel injection means M2. Is driven to inject fuel into the diesel engine M1.

When the time measured by the time measuring means M7 exceeds a predetermined reference time, the fuel injection amount increase correcting means M8 increases the fuel injection amount calculation result by the fuel injection amount calculating means M4. Further, the fuel injection control means M5 controls the fuel injection means M based on the increased fuel injection amount.
2 to control the amount of fuel injected into the diesel engine M1. That is, the star of the diesel engine M1
At a point in time when a predetermined reference time has elapsed since the start of cranking by the fuel injection, the fuel injection amount is increased at start-up.

Therefore, in the diesel engine M1 having a small friction loss and a good increase in the rotation speed, the star
The start can be completed before or after the time elapsed from the start of cranking by the motor exceeds the reference time, so that the time until the start is completed is shortened, and the fuel injection amount that is increased and corrected until the start is completed is reduced. On the other hand, in the diesel engine M1 having a large friction loss and a slowly increasing rotation speed, the fuel injection amount is increased and corrected when the time elapsed from the start of cranking by the starter exceeds the reference time. Unnecessary increase correction of the fuel injection amount is not performed until this time. Also starter
When the elapsed time from the start of cranking exceeds the reference time, the fuel injection amount is increased and corrected, and at that time, the increase in the rotational speed of the diesel engine M1 is effectively promoted.

[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.

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 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. Further, a well-known glow plug 46 as a start-up assist device is attached to each sub-combustion chamber 45.

The diesel engine 2 is provided with an intake pipe 47 and an exhaust pipe 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.

In addition, the diesel engine 2 is provided with a starter 64 for applying a rotational force by cranking at the time of start of the diesel engine 2. The starter 64 has a starter switch 65 for detecting and outputting the on / off operation. Is provided. As is well known, the starter 64 is turned on and off by the operation of an ignition switch (not shown). While the ignition switch is being operated, the starter 64 is turned on and the starter signal ST is output from the starter switch 65. It is supposed to be.

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 the VSVs 56, 61, and 62 constitute an electronic control unit that constitutes fuel injection amount calculation means, fuel injection control means, start-up determination means, clocking means, and fuel injection amount increase correction means. (Hereinafter simply referred to as “ECU”) 71, and the ECU 71 controls their 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, the intake pipe 47 has an intake air temperature sensor 7 for detecting an intake air temperature THA near the air cleaner 66.
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.
Furthermore, the transmission 6 of the diesel engine 2
7 is a magnet 7 which is rotated by the rotation of the gear.
A vehicle speed sensor 77 is provided for detecting the vehicle speed (vehicle speed) SP by turning on / off the reed switch 77b by 7a.

The ECU 71 is connected to each of the sensors 72 to 77 described above,
5 and the starter switch 65 are connected. E
The CU 71 suitably controls the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSVs 56, 61, 62 and the like based on signals output from the sensors 35, 72 to 77 and the starter switch 65.

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 an intake air temperature sensor 72, an accelerator opening sensor 73, an intake pressure sensor 74,
The water temperature sensor 75 and the starter switch 65 are connected to the buffers 88, 89, 90, 91, 92 and the multiplexer 93.
And an A / D converter 94. Similarly, the input port 85 includes the above-described 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
Are sensors 35, 7 input through the input port 85.
The detection signals of 2 to 77 and the starter switch 65 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, and the VSVs 56, 61, 62 via driving circuits 96, 97, 98, 99, 100, 101.

Then, the CPU 81 controls each of the sensors 35 and 72.
To 77 and the input values read from the starter switch 65, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46 and the VSVs 56, 61,
62 and the like are suitably controlled. Next, the processing operation of the fuel injection amount control executed by the ECU 71 will be described with reference to the flowcharts shown in FIGS. 5 and 6 and the maps shown in FIGS.

The flowcharts shown in FIGS.
1 is a processing routine for calculating a starting injection amount command value QSTA (unit is “° CA”) used for controlling the fuel injection amount at the time of starting the diesel engine 2. Then, the execution is started by a start operation of an ignition switch (not shown), and thereafter, the execution is performed by a periodic interruption every predetermined time.

When the process proceeds to this routine, first, in step 101, it is determined whether or not the CPU 81 is being initialized (initial setting). When the initialization is completed, in step 102, the engine speed NE, the starter signal ST, and the accelerator opening are determined based on the detection values of the rotation speed sensor 35, the starter switch 65, the accelerator opening sensor 73, and the water temperature sensor 75. The values of the degree ACCP and the cooling water temperature THW are read.

Subsequently, in step 103, it is determined whether or not the engine is stuck based on the previously read engine speed NE. If it is not the engine stall, it is determined in step 104 whether or not the previously read engine speed NE is a low speed of 900 rpm or less. Here, when the engine speed NE is “90”
0 rpm ”, or the previous step 1
01, if the CPU 81 is being initialized, and if it is the engine stall in step 103,
The process moves to step 115. In step 115, the fuel injection amount at the time of starting of the diesel engine 2 by cranking, that is, the starting injection amount command value Q
The increment correction value QSTNED (i) (unit is “° CA”) in the current processing cycle for calculating the STA is reset to the initial value “0”, and the process proceeds to step 116.

On the other hand, if the engine speed NE is low at 900 rpm or less at step 104, then at step 105, based on the previously read starter signal ST, whether or not the starter 64 is on. That is, it is determined whether or not cranking is performed by driving the starter 64. If the cranking is not performed by turning on the starter 64, the process proceeds to step 113. Then, in step 113, the starter operation time CSTA (unit: "second"), which is the elapsed time from the start of cranking, is reset to "0".
4, the increase correction value QST in the current processing cycle
The NED (i) is increased by the increase correction value QS in the previous processing cycle.
TNED (i-1) is set, and the routine goes to step 116.

In step 105, the starter 64
If it is cranking by turning on, step 1
At 06, the starter operating time CSTA is counted. Subsequently, in step 107, based on the previously read cooling water temperature THW, a required standby time TQSTA (unit is “second”) as a reference time corresponding to the size of the cooling water temperature THW is calculated. This required waiting time TQSTA
Is obtained by referring to a predetermined map as shown in FIG. That is, in general, the lower the engine temperature at the start is, the lower the startability of the engine is. Therefore, the required standby time TQSTA is determined according to the cooling water temperature THW corresponding to the engine temperature at each time. .

Next, at step 108, the starter operating time CSTA after the start of cranking is
It is determined whether or not the required standby time TQSTA obtained at 07 is exceeded. Here, the starter operation time CS
If the TA has not exceeded the required waiting time TQSTA, the above-described processing is executed in step 114, and the process proceeds to step 116.

On the other hand, if the starter operation time CSTA exceeds the required standby time TQSTA, step 109
, The engine speed NE in the current processing cycle
(I) and the engine speed NE in the previous processing cycle
The difference from (i-1) is calculated, and set as the rotation speed change ΔNE (unit is “rpm”) per unit time. Further, in step 110, an increase change ΔQSTNE (in units of “° CA”) of the increase correction value QSTNED according to the increase in the engine speed NE is calculated based on the obtained change in the rotation speed ΔNE. This increase change ΔQST
NE is obtained by referring to a predetermined map as shown in FIG. That is, the larger the change in the rotational speed ΔNE, the smaller the change in the increase ΔQSTNE.

Subsequently, in step 111, the amount of increase change ΔQST is calculated based on the cooling water temperature THW previously read.
A water temperature correction coefficient KQTHW for NE is calculated. The water temperature correction coefficient KQTHW is obtained by referring to a predetermined map as shown in FIG. In other words, since the lower the engine temperature, the lower the startability, the water temperature correction coefficient KQ according to the cooling water temperature THW corresponding to the engine temperature.
THW is determined.

In step 112, an increase correction value QSTNED (i) in the current processing cycle is calculated. The increase correction value QSTNED (i) is obtained by multiplying the increase change ΔQSTNE by a water temperature correction coefficient KQTHW, and calculating the increase correction value QSTNED in the previous processing cycle.
It is obtained by adding to (i-1). And step 1
12, the process proceeds from step 114 or step 115, and in steps 116 and 117, processing for setting the upper limit guard is performed on the calculated increase correction value QSTNED (i). That is, in step 116, it is determined whether or not the increase correction value QSTNED (i) is larger than “5.0 ° CA”. If not, the process directly proceeds to step 118. Also, in step 116, the increase correction value QSTNED (i) is set to "5.0 ° CA".
If it is larger than the value, in step 117, the increase correction value QSTNED (i) is set to “5.0 ° CA” as the upper limit guard value, and the process proceeds to step 118.

In step 118, a pseudo accelerator opening ACSTA at start is calculated. The starting pseudo accelerator opening ACSTA is based on the cooling water temperature TH previously read.
Based on W, it is obtained by referring to a predetermined map as shown in FIG. Subsequently, in step 119, the corrected accelerator pedal operation amount ACCPA is calculated. The corrected accelerator opening ACCPA is obtained by comparing the accelerator opening ACCP read in advance with the pseudo accelerator opening ACSTA at the start obtained in step 118 and the like.

Finally, at step 120, a starting injection amount command value QSTA is calculated. The starting injection amount command value QSTA is obtained by the starting pseudo accelerator opening ACSTA, the corrected accelerator opening ACCPA, the engine speed NE, and the increase correction value QSTN obtained in the above processing.
It is calculated according to the following formula based on ED (i) and the like. In the series of processes, the subsequent processes are temporarily terminated in step 120.

QSTA = MIN ｛65.7 + 1.17 × ACCPA− (NE ×
2.5) / 400 + QSTNED (i), 67.7 + 0.84 × ACSTA − (NE × 2.
5) / 400 + QSTNED (i)｝ In other words, in the above formula, the correction value QSTNE is an increase correction value QSTNE with respect to the basic fuel injection amount calculated from the corrected accelerator opening ACCPA, the engine speed NE, and each constant.
D (i) and pseudo accelerator opening A at start-up
An increase correction value QSTNED for the basic fuel injection amount calculated from CSTA, engine speed NE, and constants, etc.
The result obtained by adding (i) is compared, and the smaller calculation result is determined as the starting injection amount command value QSTA.

As described above, the diesel engine 2
A starting injection amount command value QSTA for controlling the fuel injection amount at the time of starting is calculated. The ECU 71 controls the timing of closing and opening the electromagnetic spill valve 23 based on the starting injection amount command value QSTA calculated as described above.
Thereby, the fuel injection amount from the fuel injection nozzle 4 at the time of starting is controlled.

As described above, according to this embodiment, in order to perform the increase correction of the fuel injection amount at the time of starting, the rotation speed change Δ
NE is calculated, and an increase change amount ΔQSTNE of the fuel injection amount is obtained in accordance with the magnitude of the rotation speed change amount ΔNE, that is, in accordance with a difference in the rising speed of the engine speed NE, and the increase change amount ΔQSTNE and the cooling water temperature Based on the water temperature correction coefficient KQTHW corresponding to THW and the increase correction value QSTNED (i-1) obtained in the previous processing cycle, the increase correction value QSTNED (i) in the current processing cycle is obtained. Then, the increase correction value QSTNED (i) is
The starting injection amount command value QSTA is determined by adding to the basic fuel injection amount obtained according to the operating state of the diesel engine 2 at the time of starting.

Therefore, according to this embodiment, in the case of the diesel engine 2 having a small friction loss and a good increase in the engine speed NE, the engine speed N
Since the rise of E is fast, the rotation speed change ΔNE increases, and a suitable increase correction value QSTNED (i) is determined according to the size of the rotation speed change ΔNE. Further, in the diesel engine 2 with a small friction loss, the start can be completed before or after the starter operation time CSTA from the start of cranking exceeds the required standby time TQSTA as a reference, and the time until the start is completed is shortened. Thus, the fuel injection amount that is increased and corrected before the start is completed decreases.

On the other hand, in the case of the diesel engine 2 having a large friction loss and a slow rise in the engine speed NE, the increase in the engine speed NE is slow, so that the speed change ΔNE becomes relatively small. A suitable increase correction value QSTN according to the magnitude of the rotation speed change ΔNE
ED (i) is determined. Therefore, the engine speed NE
In the diesel engine 2 whose rise is slow, a suitable starting injection amount command value QSTA can be determined accordingly, that is, the starting injection amount command value QSTA can be minimized, A suitable increase correction can be performed as the amount control. Moreover, in this embodiment,
In addition, since the upper limit guard of the increase correction value QSTNED (i) is set, the increase correction value QSTNED (i) is set.
Since (i) does not become unnecessarily large, it is possible to minimize the start-time injection amount command value QSTA.

In this embodiment, in the diesel engine 2 having a large friction loss, when the starter operation time CSTA from the start of cranking exceeds the required standby time TQSTA as a reference, the increase correction value QSTN
Since the fuel injection amount increase correction is performed based on ED (i), useless increase correction of the fuel injection amount is not performed until the required standby time TQSTA is exceeded. Moreover, in this case, when the elapsed time from the start of cranking exceeds the required standby time TQSTA, the fuel injection amount is reliably increased and corrected. Unlike the prior art in which the engine speed decreases, the increase in the engine speed NE is effectively promoted. As a result, the time until the start is completed can be shortened, and the fuel injection amount that is increased and corrected before the start is completed can be minimized. by this,
The fuel injection amount control at the time of starting is not performed, and unnecessary increase correction is not performed. Thus, unnecessary fuel consumption can be eliminated, and fuel efficiency can be improved.
The emission of O and HC can be reduced. In addition, the start-up time of the diesel engine 2 can be reduced while ensuring that the emission of black smoke, CO and HC is reduced.

Further, in this embodiment, the starter operating time CSTA from the start of cranking by the starter 64
Exceeds the required standby time TQSTA,
The above-described increase correction is performed, and the reference required standby time TQSTA is determined according to the magnitude of the cooling water temperature THW relative to the engine temperature. Therefore, in a state where the cooling water temperature THW is appropriately high and the engagement of the diesel engine 2 is good, the increase in the fuel injection can be corrected at an early stage, and the starting time can be further reduced. And the starting time can be reduced and the starter operating time CSTA
Is minimized, the reliability of the starter 64 can be improved, the life of the battery used to drive the starter 64 can be extended, and the charge / discharge balance can be improved. Can be improved.

It should be noted that the present invention is not limited to the above-described embodiment, and may be implemented 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 increase correction value QS according to the magnitude of the rotational speed change ΔNE per unit time at the time of starting.
TNED (i) is obtained, and when the starter operation time CSTA from the start of cranking exceeds the required standby time TQSTA, the fuel injection amount is increased and corrected based on the increased correction value QSTNED (i). Number change Δ
Even if the fuel injection amount is increased and corrected based on the uniform increase correction value when the starter operating time CSTA exceeds the required standby time TQSTA without obtaining the increase correction value QSTNED (i) according to the magnitude of NE. Good.

(2) In the above embodiment, the reference required standby time TQSTA to be compared with the starter operation time CSTA from the start of cranking is determined according to the magnitude of the cooling water temperature THW relative to the engine temperature. But
The required waiting time TQSTA may be set uniformly. (3) In the above embodiment, the present invention is embodied in the diesel engine 2 including the turbocharger 48 as a supercharger.
It can be embodied as a diesel engine with a supercharger as a supercharger or a diesel engine without a supercharger.

[0054]

As described above in detail, according to the present invention, cranking of a diesel engine by a starter is performed.
In the case of time , when the elapsed time from the start of cranking by the starter exceeds a predetermined reference time, the calculation result of the fuel injection amount is increased and corrected. The fuel injection amount can be minimized, a suitable increase correction can be made while ensuring the reduction of emission of black smoke, CO, HC, etc. in exhaust gas, and the time until the start is completed is shortened. The effect is excellent.

[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 a start-time injection amount command value calculation routine executed by an ECU according to one embodiment.

FIG. 6 is a flowchart illustrating a start-time injection amount command value calculation routine executed by an ECU according to one embodiment.

FIG. 7 is a map in which a relationship between a cooling water temperature and a required standby time in one embodiment is predetermined.

FIG. 8 is a map in which a relationship between a change in the number of revolutions and a change in the amount of increase in the embodiment is determined in advance.

FIG. 9 is a map in which a relationship between a cooling water temperature and a water temperature correction coefficient in one embodiment is predetermined.

FIG. 10 is a map in which a relationship between a cooling water temperature and a starting pseudo accelerator opening degree with respect to a cooling water temperature in one embodiment is shown.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump as a fuel injection means, 2 ... Diesel engine, 35 ... Rotation speed sensor, 65 ... Starter switch, 73 ... Accelerator opening sensor, 75 ... Water temperature sensor (35, 65, 73, 75 detect operating state. ECU 71 (constituting fuel injection amount calculation means, fuel injection control means, start time determination means, clocking means, and fuel injection amount increase correction means).

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ken Ken Ando 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-57-65821 (JP, A) JP-A-58-162738 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 41/00-41/40 F02D 1/02 311

Claims (1)

(57) [Claims] A fuel injection means for injecting fuel into a diesel engine; an operation state detection means for detecting an operation state including a rotation speed of the diesel engine; and a diesel engine based on a detection result of the operation state detection means. Fuel injection for a diesel engine, comprising: a fuel injection amount calculating unit for calculating a fuel injection amount to be injected into a fuel injection unit; and a fuel injection control unit for controlling driving of the fuel injection unit based on a calculation result of the fuel injection amount calculating unit. In the quantity control device, the time when the starter of the diesel engine is cranking based on the detection result of the operation state detecting means is determined.
A startup cranking determination means for determining bets, cranking time by the start-up cranking determination unit
When it is determined that the fuel injection amount is calculated by the fuel injection amount calculating means, when the time measured by the clocking means exceeds a predetermined reference time. A fuel injection amount control device for a diesel engine, comprising: a fuel injection amount increase correction means for increasing and correcting an amount calculation result.