JP3300394B2 - Fuel injection amount control device for diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is suitable for use in, for example, an electronically controlled diesel engine equipped with a fuel injection pump. When the accelerator pedal is depressed from the exhaust throttle operation state, the fuel injection amount from the fuel injection pump is determined. The present invention relates to a fuel injection amount control device for a diesel engine that is controlled.

[0002]

2. Description of the Related Art Conventionally, there is a case where a warm-up is promoted by operating an exhaust throttle when starting a diesel engine. However, during the warm-up operation with the exhaust throttle actuated in this way, when the accelerator pedal is depressed to increase the engine speed, the amount of fuel from the fuel injection pump is increased, There is a possibility that the injection amount may be increased before completely opening. For this reason, there is a risk that incomplete combustion of the fuel may be caused to increase the generation of smoke.

Therefore, a technique for solving the above-mentioned problem has been proposed in, for example, Japanese Utility Model Laid-Open No. 55-165834. In this technique, an operation delay device is provided between an accelerator pedal and a control lever that controls an injection amount from a fuel injection pump in conjunction with the pedal. When the accelerator pedal is depressed during the operation of the exhaust throttle, the release of the exhaust throttle is started immediately, and the fuel injection increasing timing is delayed until the predetermined accelerator opening is reached by the operation delay device. With this configuration, the fuel injection amount is increased after the exhaust throttle is released, and the generation of smoke due to a delay in releasing the exhaust throttle is reduced.

[0004]

However, when the operation delay device in the above-mentioned prior art is used, due to its structure, the time during which fuel injection is delayed in accordance with the accelerator pedal depression speed is reduced. Was different. In other words, when the accelerator pedal is depressed slowly,
When the delay time becomes long and the accelerator pedal is suddenly depressed, the delay time becomes short. Therefore, when the delay time is too long, the fuel injection amount is not increased even though the exhaust throttle is already released, and there is a problem that drivability is impaired. On the other hand, if a sufficient delay time cannot be ensured, the injection amount is increased in a state where the exhaust throttle is not released, so that there has been a problem that the occurrence of smoke increases as in the related art.

On the other hand, it is conceivable that the fuel injection timing is simply delayed for a fixed time by controlling the delay time. However, in this case, if the accelerator depression amount (accelerator opening) is too large during a certain period of time, the fuel injection amount is rapidly increased after the end of the delay, and the torque shock becomes large.
Drivability could be impaired.

The present invention has been made in view of the above-described circumstances, and has as its object to reduce the occurrence of smoke and suppress the occurrence of torque shock and the like when the exhaust throttle is released. It is an object of the present invention to provide a diesel engine fuel injection amount control device capable of performing the above.

[0007]

According to the present invention, as shown in FIG. 1, a fuel injection means M2 for injecting fuel into a diesel engine M1 is provided.
And an exhaust throttle mechanism M provided in the exhaust passage M3 of the diesel engine M1 and operated to perform exhaust throttle.
4, operating state detecting means M5 for detecting an operating state including the rotation speed and the accelerator opening of the diesel engine M1,
Exhaust throttle control means M6 for controlling the operation and release of the exhaust throttle mechanism M4 based on the detection result of the operation state detecting means M5.
A maximum injection amount calculating means M7 for calculating a maximum injection amount corresponding to the engine speed based on the detection result of the operating state detecting means M5 when the exhaust throttle mechanism M4 is released by the exhaust throttle control means M6; An exhaust throttle control unit, comprising: an injection control unit M8 for driving and controlling the fuel injection unit M2 with the maximum injection amount calculated by the maximum injection amount calculation unit M7 as an upper limit of the fuel injection amount. When the exhaust throttle mechanism M4 is released by M6, the maximum injection amount calculated by the maximum injection amount calculation means M7 is first reduced by a predetermined amount, and then the exhaust throttle amount is reduced.
A maximum injection amount changing means M9 for changing the maximum injection amount so as to gradually decrease the decrease value until the release of the release mechanism M4 is completed is provided.

[0008]

According to the above configuration, as shown in FIG. 1, during the operation of the diesel engine M1, the operating state detecting means M5 is operated.
Detects the operating state including the engine speed and the accelerator opening. Further, the exhaust throttle control means M6 controls the operation and release of the exhaust throttle mechanism M4 provided in the exhaust passage M3 based on the detection result of the operation state detecting means M5.

When the operation of the exhaust throttle mechanism M4 is released by the exhaust throttle control means M6, the maximum injection amount calculation means M7 calculates the maximum injection amount corresponding to the engine speed. At this time, the maximum injection amount changing means M9 first decreases the maximum injection amount by a predetermined amount, and then sets the exhaust throttle.
The maximum injection amount is changed so that the decrease value gradually decreases until the release of the mechanism M4 is completed . Then, the maximum injection amount changed in this way is defined as the upper limit of the fuel injection amount.
Then , the injection control means M8 drives and controls the fuel injection means M2 to control the fuel injection amount.

Therefore, since the time required from the start of the release of the operation of the exhaust throttle mechanism M4 to the completion thereof is fixed at the predetermined time, the period for reducing the maximum injection amount is determined without excess or deficiency, and the incomplete fuel supply is performed. Combustion is suppressed.

[0011] Further, since the reduced value reduced by the predetermined amount by the maximum injection amount changing means M9 is gradually reduced,
The fuel injection amount is increased in accordance with the degree of release of the operation of the exhaust throttle mechanism M4. Therefore, the fuel injection amount does not suddenly increase immediately after the release of the operation of the exhaust throttle mechanism M4 is completed.

[0012]

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 timing control device for a supercharged diesel engine in this embodiment, and FIG. 3 is a sectional view showing the distribution type fuel injection pump 1. The fuel injection pump 1 as a fuel injection means 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, the 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 attached to the cam plate 8 so as to be integrally rotatable. 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 a coupling (not shown), so that the cam plate 8 rotates and engages with the cam roller 10 to rotate in the left-right direction by the same number as the number of cylinders. Is reciprocated. 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 1 is moved while the cam face 8a rides down the cam roller 10.
2 is reactivated.

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 via 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.

The pump housing 13 is provided with a spill passage 22 for fuel spill that connects the high-pressure chamber 15 and the fuel chamber 21. An electromagnetic spill valve 23 for adjusting fuel spill from the high-pressure chamber 15 is provided in the middle of the spill passage 22. The electromagnetic spill valve 23 is a normally open type valve. When the coil 24 is not energized (off), the valve body 25 is opened and fuel in the high-pressure chamber 15 is spilled to the fuel chamber 21. When the coil 24 is energized (turned on), the valve body 25 is closed, and the spill of fuel from the high-pressure chamber 15 to the fuel chamber 21 is stopped.

Therefore, by controlling the energizing time of the electromagnetic spill valve 23, the valve 23 is controlled to close and open, and the spill amount of fuel from the high-pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel 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 (expanded at 90 degrees in this figure) 26 for controlling the fuel injection timing. The timer device 26 changes the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5, thereby changing the timing at which the cam face 8a engages with the cam roller 10, that is, the reciprocating drive timing of the cam plate 8 and the plunger 12. It is for.

The timer device 26 is driven by hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the housing 27, and a 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 a slide pin 32.

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 (hereinafter, referred to as “timer piston position”) is determined based on the balance between the fuel pressure and the urging force of the timer spring 31. Further, by determining the timer piston position, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 via the cam plate 8 is determined.

The timer device 26 is provided with a timer control valve (TCV) 33 for adjusting the fuel pressure acting as the oil pressure of the timer device 26. That is, the pressurizing chamber 30 and the low-pressure chamber 29 of the timer housing 27 are communicated with each other by the communication passage 34, and the TCV 3
3 are provided. The TCV 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 TCV 33. The lift timing of the plunger 12 is controlled by adjusting the fuel pressure.
The fuel injection timing from each fuel injection nozzle 4 is controlled.

On the upper part of the roller ring 9, a rotation speed sensor 35 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,
A sub-combustion chamber 45 communicating with each of the main combustion chambers 44 is provided for each cylinder. And each sub-combustion chamber 45
Is supplied with fuel injected from each fuel injection nozzle 4. 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 48 as an exhaust passage, and the intake pipe 47 has a turbocharger 4 constituting a supercharger.
Nine compressors 50 are provided, and the exhaust pipe 48 is provided with a turbine 51 of a turbocharger 49.
The exhaust pipe 48 is provided with a waste gate valve 52 for adjusting the supercharging pressure PiM. As is well known, the turbocharger 49 uses the energy of the exhaust gas to rotate the turbine 51, and rotates the compressor 50 on the same axis as the turbine 51 to increase the pressure of the intake air. By this action, high-density air 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 4
A recirculation pipe 54 for recirculating a part of the exhaust gas in 8 to the suction port 53 of the intake pipe 47 is provided. 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 is provided in the middle of the intake pipe 47 so as to open and close in accordance with the amount of depression of an accelerator pedal 57. 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.

An exhaust throttle valve 64 for closing an exhaust passage is provided in the exhaust pipe 48 to warm up the diesel engine 2. A diaphragm type exhaust throttle actuator 65 is provided to open and close the exhaust throttle valve 64, and a rod 66 thereof is connected to the exhaust throttle valve 64 via a link 67. The exhaust throttle actuator 65 is operated by introducing a negative pressure, and is connected to the exhaust throttle VSV 69 through a negative pressure passage 68. An exhaust throttle mechanism is configured by the exhaust throttle valve 64, the exhaust throttle actuator 65, the exhaust throttle VSV 69, and the like. When the exhaust throttle VSV 69 is turned on and opened, a vacuum pump (not shown) is moved from the exhaust throttle actuator to the exhaust throttle actuator. Negative pressure is introduced into the valve 65, and the rod 66 contracts so that the exhaust throttle valve 64 is closed. That is, the exhaust throttle is performed.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above
3, TCV33, glow plug 46 and each VSV56,
61, 62, 69 are electrically connected to an electronic control unit (hereinafter simply referred to as “ECU”) 71 constituting exhaust throttle control means, maximum injection amount calculation means, injection control means and maximum injection amount change means, respectively. The drive timing is controlled by the ECU 71.

As sensors constituting the operating state detecting means of the diesel engine 2, the following various sensors are provided in addition to the rotation speed sensor 35. That is, the intake pipe 47
An intake air temperature sensor 72 for detecting the intake air temperature THA is provided in the vicinity of an air cleaner 70 provided at the inlet of the air conditioner. Further, the accelerator opening ACCP corresponding to the load of the diesel engine 2 is determined based on the open / close position of the throttle valve 58.
Is provided with an accelerator opening sensor 73 for detecting the acceleration.
An intake pressure sensor 74 that detects the intake air pressure after supercharging by the turbocharger 49, that is, the supercharging pressure PiM is provided near the intake port 53. Further, a water temperature sensor 75 for detecting the cooling water temperature THW of the diesel engine 2 is provided. Further, a crank angle sensor 76 for detecting a rotation reference position of the crankshaft 40, for example, a rotation position of the crankshaft 40 with respect to a top dead center of a specific cylinder is provided. Further, a transmission (not shown) has a magnet 77a which is turned by rotation of the gear.
A vehicle speed sensor 77 for turning on / off the reed switch 77b to detect a vehicle speed (vehicle speed) SP is provided.

The ECU 71 is connected to each of the sensors 72 to 77 described above,
5 is connected. In addition, the ECU 71 controls each sensor 35,
Based on the detection signals output from 72 to 77, the electromagnetic spill valve 23, the TCV 33, the glow plug 46, and the VSV 5
6, 61, 62, 69, 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 is provided with the above-described intake air temperature sensor 72, accelerator opening sensor 73, intake pressure sensor 74, and water temperature sensor 75 in the buffers 88, 89, 90, and 9 respectively.
1, a 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 via a waveform shaping circuit 95. Then, the CPU 81 reads, as input values, detection signals of the sensors 35, 72 to 77, etc., which are input through the input port 85. Each drive circuit 9 is connected to the output port 86.
The electromagnetic spill valve 23, the TCV 33, the glow plug 46, the VSVs 56, 61, 62, 69, etc. are connected via 6, 97, 98, 99, 100, 101, 102.

The CPU 81 controls the sensors 35 and 72
Based on the input value read from ~ 77, the electromagnetic spill valve 2
3, TCV33, glow plug 46 and VSV56,6
1, 62, 69, etc. are suitably controlled.

Next, the processing operation of the fuel injection amount control executed by the ECU 71 will be described with reference to FIGS. The flowcharts shown in FIGS.
1 is a processing routine for controlling the fuel injection amount in the fuel injection pump 1,
It is executed by a periodic interruption every predetermined time. Note that this flowchart describes only the processing when the diesel engine 2 is started. At the time of this start, the operation of the exhaust throttle is started by a separate routine.

When the processing shifts to this routine, first, at step 101, the engine speed N is detected by the detecting means such as the speed sensor 35 and the accelerator opening sensor 73.
E and the accelerator opening ACCP are read, and the exhaust throttle release initialization flag F is read. The exhaust throttle release initialization flag F is processed in a separate routine, and is set to "1" when the operation of the exhaust throttle is started.

Next, at step 102, the basic fuel injection amount QBASE is calculated. This basic injection amount QBA
The calculation of SE is performed based on the previously read engine speed NE and accelerator opening ACCP. That is,
The basic injection amount QBASE is calculated with reference to a predetermined map using the engine speed NE and the accelerator opening ACCP as parameters. In calculating the basic injection amount QBASE, the cooling water temperature THW, the accelerator opening ACCP and the engine speed NE are calculated as necessary.
Based on these values, the low-temperature start increase correction, the acceleration increase correction, the deceleration increase correction, and the like are performed.

Subsequently, in step 103, it is determined whether or not the vehicle is currently idling based on the accelerator opening ACCP previously read. If the current state is the idling state, the process proceeds to step 104.

In step 104, the idle injection amount QIDLE is calculated. This idle injection amount QIDL
E is calculated based on a predetermined reference value, and is appropriately corrected according to the temperature and the like at that time. Then, in the next step 105, the idle injection amount QI
DLE is set as the final injection amount QFIN.

Subsequently, at step 106, an injection amount command value VSSP corresponding to the final injection amount QFIN is obtained. Then, in step 107, the obtained injection amount command value VSSP is output, that is, the basic injection amount Q
The drive of the electromagnetic spill valve 23 is controlled based on the injection amount command value VSSP corresponding to BASE, and the subsequent processing is temporarily terminated.

On the other hand, if the current state is not the idling state in step 103, the exhaust throttle VSV 69 is turned off and the exhaust throttle valve 64 is turned off in the next step 108.
Open and release the exhaust throttle.

In step 109, it is determined whether the exhaust throttle release initialization flag F read in step 101 is "1". If the exhaust throttle release initialization flag F is not "1", the process proceeds to step 113, which will be described later, assuming that the exhaust throttle release has been started. When the exhaust throttle release initialization flag F is “1”, it is determined that the exhaust throttle release is to be started, and in step 110, the count value C for counting a predetermined time T is set to “0”. Reset to "."

Next, at step 111, the exhaust throttle coefficient K is set to an initial value α (where 0 <α <1). That is, the exhaust throttle coefficient K is set to the initial value α at the same time as the release of the exhaust throttle is started, as shown in the preset map of FIG. The exhaust throttle coefficient K is a value that is gradually increased to “1” until a predetermined time T elapses after being set to the initial value α. However, the predetermined time T is theoretically or experimentally obtained in advance as a time from the start of the release of the exhaust throttle to the completion thereof.
In step 112, the exhaust throttle release initialization flag F is reset to "0", and the routine goes to the next step 113.

Then, the process proceeds from step 109 or step 112, and in step 113, it is determined whether or not the exhaust throttle coefficient K is "1". When the exhaust throttle coefficient K is “1”, it is determined that the predetermined time T has elapsed and the release of the exhaust throttle has been completed, and the process proceeds to step 116 described below.

If the exhaust throttle coefficient K is not "1", the routine proceeds to step 114 on the assumption that the predetermined time T has not yet elapsed and the release of the exhaust throttle has not been completed. Then, in step 114, the exhaust throttle coefficient K corresponding to the elapsed time is calculated based on the count value C with reference to the map of FIG. Further, in step 115, only “1” is added to the count value C of the counter to set it as a new count value C, and the process proceeds to the next step 116.

Then, step 113 or step 11
5 and at step 116, the maximum injection amount QFU is determined based on the engine speed NE and the exhaust throttle coefficient K.
LL is calculated. At this time, the maximum injection amount QFULL
Is based on the engine speed NE, and as shown in FIG.
The relationship of AX is obtained by obtaining a full load injection amount QMAX with reference to a predetermined map, and multiplying the full load injection amount QMAX by an exhaust throttle coefficient K.

Thereafter, in step 117, it is determined whether or not the basic injection amount QBASE calculated in the previous step 102 is smaller than the maximum injection amount QFULL calculated in step 116.

If the basic injection amount QBASE is smaller than the maximum injection amount QFULL, in step 118, the basic injection amount QBASE is set to the final injection amount QFIN. Subsequently, at step 106, an injection amount command value VSSP corresponding to the final injection amount QFIN is obtained.
Then, in step 107, the obtained injection amount command value VSSP is output, that is, the basic injection amount QBAS
The drive of the electromagnetic spill valve 23 is controlled based on the injection amount command value VSSP corresponding to E, and the subsequent processing is temporarily terminated.

If the basic injection amount QBASE is larger than the maximum injection amount QFULL in step 117, the maximum injection amount QFULL is set in step 119.
Is the final injection amount QFIN. Subsequently, step 106
, An injection amount command value VSSP corresponding to the final injection amount QFIN is determined. Then, in step 107, the obtained injection amount command value VSSP is output, that is, the injection amount command value VS corresponding to the maximum injection amount QFULL.
The drive of the electromagnetic spill valve 23 is controlled based on the SP, and the subsequent processing is temporarily terminated.

As described above, the fuel injection amount control at the time of starting is executed. As described above, according to the fuel injection amount control device of this embodiment, after the predetermined time T has elapsed, the maximum injection amount QFULL is calculated with reference to the map of FIG. Until the time T elapses, the calculation is performed by multiplying the full load injection amount QMAX obtained from the map of FIG. 8 by the exhaust throttle coefficient K. Accordingly, the maximum injection amount QFULL is smaller than after the elapse of the predetermined time T until a predetermined time T elapses after the release of the exhaust throttle is started, that is, until the release of the exhaust throttle is completed. Therefore, the fuel is not excessively supplied to the diesel engine 2 until the release of the exhaust throttle is completed, and the incomplete combustion of the fuel is suppressed, and the generation of smoke can be reduced.

Further, in this embodiment, the predetermined time T is a time from the start of the release of the exhaust throttle to the time when the reduction value of the maximum injection amount QFULL becomes zero, and is always a fixed time. Therefore, the maximum injection amount QFULL is set. The period during which the weight is reduced is determined without excess or shortage. Therefore, even if there is a difference in the depressing speed of the accelerator pedal 57, the speed difference is avoided because the drivability is impaired due to a torque shock or the like, and the generation of smoke due to incomplete combustion increases. can do.

Further, in this embodiment, since the maximum injection amount QFULL is reduced by a predetermined amount at the same time as the release of the exhaust throttle, the reduction amount is gradually decreased. , The fuel injection amount is smoothly increased. Therefore, the fuel injection amount does not suddenly increase immediately after the exhaust throttle release is completed, and it is possible to prevent the occurrence of torque shock due to the sudden increase in the fuel injection amount.

As described above, in this embodiment, when the exhaust throttle is released, it is possible to both reduce the occurrence of smoke and suppress the occurrence of torque shock and the like.
Note that the present invention is not limited to the above embodiment,
A part of the configuration may be appropriately changed without departing from the spirit of the invention, and the invention may be implemented as follows.

(1) In the above embodiment, as shown in FIG. 7, the exhaust throttle coefficient K reduced to the initial value α simultaneously with the start of the exhaust throttle increases linearly in proportion to the elapsed time. However, the way of increasing the exhaust throttle coefficient K may be curved.

(2) In the above embodiment, the diesel engine 2 having the turbocharger 49 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.

(3) In the above embodiment, the exhaust throttle for promoting warm-up has been described. However, the present invention may be embodied in a diesel engine equipped with an exhaust brake using an exhaust throttle released by depressing an accelerator pedal.

[0059]

As described above in detail, according to the present invention, when the operation of the exhaust throttle mechanism is released, the maximum injection amount is first reduced by a predetermined amount, and then the exhaust throttle device is reduced.
Since the maximum injection amount was changed so as to gradually decrease the weight loss value until the release of the gaze was completed ,
This provides an excellent effect that both the generation of smoke can be reduced and the generation of torque shock and the like can be suppressed.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram showing a fuel injection amount control device for a supercharged 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 showing a configuration of an ECU and the like in one embodiment.

FIG. 5 is a flowchart illustrating a processing routine for controlling a fuel injection amount in one embodiment.

FIG. 6 is a flowchart illustrating a continuation of a processing routine for fuel injection amount control in one embodiment.

FIG. 7 is a map showing a relationship between an exhaust throttle coefficient and a count value of a predetermined time in one embodiment.

FIG. 8 is a map showing a relationship between a predetermined full load injection amount and an engine speed in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump as fuel injection means, 2 ... Diesel engine, 35 ... Rotation speed sensor as operation state detection means, 48 ... Exhaust pipe as exhaust passage, 64 ... Exhaust throttle valve, 65 ... Exhaust throttle actuator, 69: VSV for exhaust throttle (64, 65, 69 constitute an exhaust throttle mechanism), 71: ECU constituting exhaust throttle control means, maximum injection amount calculation means, injection amount control means, and maximum injection amount change means , 73... Accelerator opening sensor as operating state detecting means.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shigeru Maeda 1-1 1-1 Showa-cho, Kariya-shi, Aichi Japan Denso Co., Ltd.

Claims (1)

(57) [Claims] 1. A fuel injection means for injecting fuel into a diesel engine, an exhaust throttle mechanism provided in the exhaust passage of the diesel engine and operated to perform exhaust throttle, a rotational speed and an accelerator opening of the diesel engine Operating state detecting means for detecting an operating state including the degree, exhaust throttle controlling means for controlling the operation and release of the exhaust throttle mechanism based on the detection result of the operating state detecting means, and exhaust gas by the exhaust throttle controlling means. maximum injection aperture mechanism when it is released, the maximum injection amount calculating means for calculating a maximum injection quantity corresponding to the engine speed based on the detection result of said operating condition detecting means, for calculating the maximum injection amount calculation means Fuel injection amount
An injection control means for driving and controlling the fuel injection means as an upper limit value of the radiation amount, a fuel injection amount control device for a diesel engine comprising: when the exhaust throttle mechanism is released by the exhaust throttle control means, The maximum injection amount calculated by the maximum injection amount calculation means is first reduced by a predetermined amount, and thereafter the maximum injection amount is gradually reduced until the release of the exhaust throttle mechanism is completed. A fuel injection amount control device for a diesel engine, comprising a maximum injection amount changing means for changing an injection amount.