JPH07150998A - Control method for fuel injection quantity of diesel engine - Google Patents

Abstract

PURPOSE:To dissolve tardy acceleration so as to insure favorable acceleration feeling, while surely preventing generation of acceleration shock at acceleration. CONSTITUTION:An ECU (electronic control device) 71 performs averaging control in which a fuel injection quantity to be fed to a diesel engine 2 is gradually increased a prescribed increasing quantity by a prescribed increasing quantity at acceleration. When the accelerator opening before detecting acceleration is larger than '0%', the ECU 71 performs averaging control of acceleration by a larger increasing quantity than that in case of the accelerator opening of '0%'. Hereby, at accelerating from the low load condition of accelerator opening of '0%' in which the acceleration shock is maximum, the fuel injection quantity is relatively gradually increased, and hence generation of acceleration shock is surely prevented. Meanwhile, at accelerating from the condition of accelerator opening larger than '0%' in which the acceleration shock hardly causes any problems, the fuel injection quantity is relatively quickly increased so as to dissolve tardy acceleration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine applied to, for example, an automobile, and more particularly to a fuel injection amount control method for performing a moderation control for gradually increasing the fuel injection amount during acceleration.

[0002]

2. Description of the Related Art Conventionally, as this type of technique, for example, one disclosed in Japanese Patent Application Laid-Open No. 60-122246 is known. In this conventional technique, so-called smoothing control is performed in which the fuel injection amount to be supplied to the diesel engine at the time of acceleration is gradually increased by a predetermined increase value to approach the target value. By performing this moderation control, a rapid change in the fuel injection amount during acceleration is suppressed and the acceleration shock is alleviated.

Further, in this prior art, when the accelerator pedal is depressed to start acceleration, the fuel injection amount before acceleration is set to correspond to the fuel injection amount at which driving force starts to be applied to a vehicle equipped with a diesel engine. If it is smaller than the value, the fuel injection amount is brought up to the set value once.
Then, the smoothing control is started with the set value as an initial value to gradually bring the fuel injection amount close to the target value corresponding to the depression amount of the accelerator pedal. If the fuel injection amount before acceleration is equal to or more than the set value, the fuel injection amount before acceleration is used as the initial value to start the smoothing control so that the fuel injection amount gradually approaches the target value. ing. Therefore, according to this conventional technique, the time lag from when the accelerator pedal is depressed until the driving force starts to be applied to the vehicle can be eliminated while surely preventing the occurrence of an acceleration shock, and a good accelerator response can be obtained. Obtainable.

[0004]

However, in the above prior art, the smoothing control is performed with the same increase value regardless of whether the fuel injection amount before acceleration is equal to or more than the set value. .

By the way, when the fuel injection amount is smaller than the set value, for example, when the accelerator opening is "0%", almost no driving force is applied to the automobile and the load of the diesel engine is low. Then, when the accelerator pedal is depressed from such a low load state to start acceleration, the drive system including the engine is twisted or rattles, causing a large acceleration shock. However, when the fuel injection amount is equal to or larger than the set value, the accelerator pedal is depressed to some extent and the driving force is applied to the vehicle. Therefore, even if the accelerator pedal is further stepped on from this state to start acceleration, the acceleration shock generated is small, and the acceleration shock does not become a serious problem.

Therefore, when the fuel injection amount before acceleration is equal to or larger than the set value, it is not necessary to perform the smoothing control with the same increase value as when the fuel injection amount before acceleration is smaller than the set value. Rather, in the conventional technique, when the fuel injection amount is accelerated from the state of being equal to or higher than the set value, the increase amount of the fuel injection amount in the smoothing control is too small, and the fuel injection amount is not increased promptly. However, there is a problem in that the acceleration feels slow and the acceleration feeling is impaired.

The present invention has been made to solve the above problems, and an object thereof is to reliably prevent the occurrence of an acceleration shock at the time of acceleration, and to eliminate the delay of acceleration to obtain a good acceleration fee. (EN) A fuel injection control method for a diesel engine that can secure a ring.

[0008]

In order to achieve the above object, in the invention described in claim 1, the engine operating state including the engine speed and the accelerator opening is detected, and the detected engine operating state is set. The fuel injection amount control of the diesel engine that determines whether or not the vehicle is accelerating based on the acceleration, and gradually increases the fuel injection amount to be supplied to the diesel engine by a predetermined increase value during acceleration. In the method, when the fuel injection amount or accelerator opening before acceleration detection is larger than a predetermined value, the smoothing control is performed with a larger increase value when the fuel injection amount or acceleration opening before acceleration detection is less than or equal to a predetermined value. It is characterized by doing so.

Further, the invention according to claim 2 is characterized in that the increase amount is changed based on whether or not the accelerator opening degree before acceleration detection is larger than zero.

[0010]

Therefore, according to the first aspect of the present invention, the engine operating state including the engine speed and the accelerator opening is detected, and whether or not it is during acceleration is detected based on the detected engine operating state. To be judged. Then, when it is determined that it is during acceleration, the fuel injection amount to be supplied to the diesel engine is gradually increased by a predetermined increase value,
Smoothing control is performed.

At this time, if the fuel injection amount or accelerator opening before acceleration detection is larger than a predetermined value, the fuel injection amount before acceleration detection or accelerator opening is an increase value larger than a predetermined value. Control is performed.

That is, for example, when the fuel injection amount or accelerator opening before acceleration detection is larger than a predetermined value and the acceleration shock does not pose a serious problem, the fuel injection amount is increased relatively quickly. As a result, the time required for the smoothing control is shortened, and the rattling of acceleration is eliminated.
On the other hand, for example, when the fuel injection amount before acceleration detection or the accelerator opening is equal to or less than a predetermined value and the load is low such that acceleration shock becomes a problem, the fuel injection amount is increased relatively slowly. As a result, the time required for the smoothing control becomes longer,
The occurrence of acceleration shock is prevented.

According to the second aspect of the present invention, when the accelerator opening before the acceleration is detected is 0, the smoothing control is performed with a smaller increase value when the accelerator opening before the acceleration is detected is larger than 0. Is done. That is, the fuel injection amount is relatively gradually increased only during acceleration from the time when the accelerator opening with the largest acceleration shock is 0, and the occurrence of the acceleration shock is reliably prevented. On the other hand, during acceleration when the accelerator opening is less than 0, where acceleration shock is less of a problem, the fuel injection amount is increased relatively quickly, and acceleration control that emphasizes acceleration over acceleration shock is performed. Is done. Further, since the increase value is changed by a simple judgment as to whether or not the accelerator opening degree before acceleration detection is larger than 0, the judgment operation does not become complicated,
There is no risk of malfunction.

[0014]

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

FIG. 7 is a schematic configuration diagram showing a fuel injection amount control device for a diesel engine with a supercharger in this embodiment, and FIG. 8 is a sectional view showing the distribution type fuel injection pump 1. The fuel injection pump 1 includes a drive pulley 3 drivingly connected to a crankshaft 40 of a diesel engine 2 via a belt or the like. Then, the rotation of the drive pulley 3 drives the fuel injection pump 1,
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 through a coupling (not shown), the cam plate 8 rotates and engages with the cam roller 10, and the same number as the number of cylinders in the left-right direction in the figure. Is driven back and forth. Also, the plunger 12 is reciprocally driven in the same direction while rotating with the reciprocating motion. That is, the plunger 12 is moved forward (lifted) while the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, and vice versa.
2 is reactivated.

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

Then, the drive shaft 5 is rotated and the fuel feed pump 6 is driven, whereby fuel is supplied from a fuel tank (not shown) into the fuel chamber 21 through the fuel supply port 20. Further, during the suction stroke in which the plunger 12 is returned and the high pressure chamber 15 is depressurized, the suction groove 1
The fuel is introduced from the fuel chamber 21 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 is formed with a spill passage 22 for fuel overflow (spill) which connects the high pressure chamber 15 and the fuel chamber 21. An electromagnetic spill valve 23 as a spill adjusting valve for adjusting the fuel spill from the high pressure chamber 15 is provided in the middle of the spill passage 22. The electromagnetic spill valve 23 is a normally open type valve, and the valve body 25 is opened to spill the fuel in the high pressure chamber 15 to the fuel chamber 21 when the coil 24 is not energized (OFF). When the coil 24 is energized (turned on), the valve body 25 is closed and the spill of fuel from the high pressure chamber 15 to the fuel chamber 21 is stopped.

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

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

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

In the pressure chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. 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.

The timer device 26 is provided with a timer control valve (TCV) 33 in order to adjust the fuel pressure acting as the control oil pressure of the timer device 26. That is, the pressurizing chamber 30 and the low pressure chamber 29 of the timer housing 27 communicate with each other through the communication passage 3
4 are connected to each other, and a TV is provided on the way of the communication passage 34.
C33 is provided. The TVC 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 TVC 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 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 3
The reference numeral 5 indicates a timing signal corresponding to the engine speed NE by detecting passage of the protrusions of the pulsar 7 when the protrusions and the like of the pulsar 7 cross each other.
That is, the engine rotation pulse is output for each constant crank angle (11.25 ° CA). Also, this rotation speed sensor 35
Detects the instantaneous rotation speed for each engine rotation pulse. Further, since this rotation speed sensor 35 is integrated with the roller ring 9, it outputs a reference timing signal to the plunger lift at a constant timing regardless of the control operation of the timer device 26.

Next, the diesel engine 2 will be described. In the diesel engine 2, a main combustion chamber 44 corresponding to each cylinder is formed by the cylinder 41, the piston 42 and the cylinder head 43. or,
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 has an intake passage 47.
And an exhaust passage 48 are provided respectively. The intake passage 47 is provided with a compressor 50 of a turbocharger 49 that constitutes a supercharger, and the exhaust passage 48 is provided with a turbine 51 of the turbocharger 49. or,
A wastegate valve 52 for adjusting the supercharging pressure PiM is provided in the exhaust passage 48. As is well known, the turbocharger 49 uses the energy of exhaust gas to rotate the turbine 51 and the compressor 50 coaxial with the turbine 51 to increase the intake air pressure. 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.

Further, the diesel engine 2 is provided with an EGR passage 54 for returning a part of the exhaust gas in the exhaust passage 48 to the intake port 53 of the intake passage 47. And
In the middle of the EGR passage 54, an exhaust gas recirculation valve (EGR) for adjusting the recirculation amount of exhaust gas is provided.
Valve) 55 is provided. This EGR valve 55
Is controlled to be opened / closed by controlling a vacuum switching valve (VSV) 56.

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

The electromagnetic spill valve 2 provided in the fuel injection pump 1 and the diesel engine 2 as described above.
3, TCV33, glow plug 46 and each VSV56,
The electronic control units 61 and 62 are electrically connected to an electronic control unit (hereinafter simply referred to as “ECU”) 71, and their drive timing is controlled by the ECU 71.

As a sensor for detecting the operating state of the diesel engine 2, the following various sensors are provided in addition to the rotation speed sensor 35. That is, the intake passage 47
An intake air temperature sensor 72 for detecting the intake air temperature THA is provided near the air cleaner 64 provided at the inlet of the. Further, an accelerator position sensor 73 that is operated in conjunction with the accelerator pedal 57 is provided. The accelerator position sensor 73 detects the accelerator opening ACCP corresponding to the load of the diesel engine 2 and changes the accelerator opening ACCP per unit time.
That is, the depression speed ΔACP of the accelerator pedal 57 is detected. Further, the accelerator position sensor 73 has an idle switch 73a, which is turned on when the accelerator pedal 57 is not depressed and the accelerator opening ACCP is "0%", and the accelerator pedal 57 is depressed. When the accelerator opening ACCP is larger than "0%", the accelerator opening is turned off.

An intake pressure sensor 74 for detecting 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. Also, the rotation reference position of the crankshaft 40 of the diesel engine 2,
For example, the crankshaft 40 for the top dead center of a 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) SPD 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 is connected. Further, the ECU 71 uses the sensors 35,
The electromagnetic spill valve 23, the TCV 33, the glow plug 46, and the VSV based on the detection signals output from 72 to 77.
56, 61, 62 and the like are preferably controlled.

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

The intake port temperature sensor 72, the accelerator position sensor 73, and the same sensor 73 are connected to the input port 85.
Of the idle switch 73a, the intake pressure sensor 74, and the water temperature sensor 75 are connected to the buffers 88, 89, 90, 91, 9 respectively.
2, connected via a multiplexer 93 and an A / D converter 94. Similarly, the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 described above are connected to the input port 85 via a waveform shaping circuit 95. Then, the CPU 81 reads the detection signals of the sensors 35, 72 to 77, etc., which are input via the input port 85, as input values. Also, each drive circuit 9 is connected to the output port 86.
6,97,98,99,100,101 via electromagnetic spill valve 23, TCV33, glow plug 46 and VSV
56, 61, 62, etc. are connected.

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

Next, the processing operation of the fuel injection amount control executed by the above-mentioned ECU 71 will be described with reference to FIGS. The flowcharts shown in FIGS. 1 and 2 are
Among the processes executed by the ECU 71, it is a main routine for controlling the fuel injection amount in the fuel injection pump 1 and is executed by a regular interruption every predetermined time.

When the processing shifts to this routine, first, at step 101 shown in FIG. 1, the rotation speed sensor 35,
Based on the detection signals from the accelerator position sensor 73, the vehicle speed sensor 77, etc., the engine speed NE, the accelerator opening ACCP, the accelerator depression speed ΔACP, the vehicle speed SPD, etc. are read. At the same time, based on the on / off signal from the idle switch 73a of the accelerator position sensor 73, the on / off of the switch 73a is turned on / off.
Read off state.

Next, at step 102, the fuel injection amount QGOV is calculated based on the previously read accelerator opening ACCP and the like. That is, the calculation of the fuel injection amount QGOV is performed with reference to a predetermined map (not shown) having the accelerator opening ACCP and the like as parameters. Then, in step 103, the calculated fuel injection amount Q is calculated based on the previously read engine speed NE.
The GOV is corrected and the corrected fuel injection amount QGOVT is calculated.

Next, at step 104, it is judged if the previously read vehicle speed SPD is equal to or higher than a predetermined vehicle speed. Here, when the vehicle speed SPD is not equal to or higher than the predetermined vehicle speed, in step 105, the calculated fuel injection amount QGOVT after correction is directly used as the basic injection amount QB for this time.
Set as ASE. That is, for example, if acceleration smoothing control is performed at the time of starting the vehicle, the vehicle will start poorly and smooth starting cannot be performed. Therefore, when the vehicle speed SPD is not equal to or higher than a predetermined vehicle speed such as when the vehicle starts, the accelerator opening degree AC is not performed without performing the acceleration smoothing control.
The fuel injection amount QGOVT calculated based on CP,
The basic injection amount QBASE of this time is set as it is.

Thereafter, in step 118 shown in FIG. 2, the set basic injection amount QBASE is corrected on the basis of the various engine operating conditions previously read,
The final injection amount QFIN is calculated. Then, step 11
9, the injection amount command value TSP corresponding to the final injection amount QFIN is calculated, and the calculated injection amount command value T
Output SP. That is, the fuel is supplied from the fuel injection pump 1 to the diesel engine 2 by drivingly controlling the electromagnetic spill valve 23 based on the injection amount command value TSP corresponding to the final injection amount QFIN. Then, in step 120, the final injection amount QFIN in the current control cycle is set as the injection amount in the previous injection (previous injection amount) QBSEOL for the next injection, and the subsequent processing is once ended.

On the other hand, in step 104 shown in FIG. 1, when the vehicle speed SPD is equal to or higher than the predetermined vehicle speed, the process proceeds to step 106. In step 106, the fuel injection amount QGOVT calculated this time is the previous injection amount QBSEO.
It is determined whether or not it is larger than L. Here, if the fuel injection amount QGOVT is not larger than the previous injection amount QBSEOL, it is determined that the vehicle is not in the accelerating state and the above-described step 10 is performed.
5 and steps 105 and 11 as described above.
8 to 120 are executed.

If it is determined in step 106 that the current fuel injection amount QGOVT is larger than the previous fuel injection amount QBSEOL, it is determined that the vehicle is in an accelerating state, and step 10 is executed.
Move to 7. In step 107, it is determined whether the current fuel injection amount QGOVT is larger than the smoothing start injection amount QRL. Here, the smoothing start injection amount QRL
Is an injection amount corresponding to a fuel injection amount at which driving force starts to be applied to a vehicle equipped with the diesel engine 2, and is not shown based on various engine operating states such as the engine speed NE previously read. It is calculated according to a predetermined map, calculation formula, or the like.

If it is determined in step 107 that the current fuel injection amount QGOVT is not larger than the smoothing start injection amount QRL, it is determined that it is not necessary to perform the acceleration smoothing control, and the process proceeds to step 105, which has already been described. As described above, the processes of steps 105 and 118 to 120 are executed. If the current fuel injection amount QGOVT is larger than the smoothing start injection amount QRL, the routine proceeds to step 108.

In step 108, the previous injection amount Q
It is determined whether BSEOL is smaller than the annealing start injection amount QRL. Here, if the previous injection amount QBSEOL is smaller than the smoothing start injection amount QRL, step 1
In step 09, the smoothing start injection amount QRL is set as the final injection amount QFIN for this time. After that, the process proceeds to step 119 shown in FIG. 2 and the processes of steps 119 to 120 are executed. That is, fuel is supplied to the diesel engine 2 based on the injection amount command value TSP corresponding to the smoothing start injection amount QRL. As a result, the time lag from the depression of the accelerator pedal 57 to the start of the driving force applied to the automobile can be eliminated, and a good accelerator response can be obtained.

On the other hand, in step 108 shown in FIG. 1, the previous injection amount QBSEOL is set to the anneal start injection amount QRL.
If not less than step 110 shown in FIG.
Move to. In step 110, the time (idle off time) CIDLOF from when the idle switch 73a is turned off (idle off time) is within a preset predetermined time KOF based on the previously read on / off state of the idle switch 73a. Determine whether or not. The idle off time CIDLOF is measured by a counter included in the CPU 81. Then, based on the on / off state of the idle switch 73a previously read,
When the switch 73a is turned off, measurement of the idle off time CIDLOF is started, and when the idle switch 73a is turned on, the measurement time is cleared.

Then, in step 110, when the idle off time CIDLOF is within the predetermined time KOF, it is assumed that the accelerator pedal 57 is depressed from the state where the accelerator opening ACCP is "0%" to start acceleration. Control goes to step 111. In step 111, the first smoothing increase value QSMA1 is calculated based on the accelerator opening ACCP and the accelerator depression speed ΔACP that have been read in advance. This first smoothed increase value QSM
As shown in FIGS. 3 and 4, the calculation of A1 is performed with reference to a predetermined map having the accelerator opening ACCP and the accelerator depression speed ΔACP as parameters.

That is, first, based on the accelerator opening ACCP, the first smoothed increase value QSMAA1 is obtained with reference to the solid line of the map shown in FIG. That is, the solid line in the map of FIG. 3 indicates the value that the first smoothed increase value QSMAA1 should take in correspondence with the accelerator opening ACCP. Also, based on the accelerator pedal depression speed ΔACP,
The first smoothed increase value QSMAAC1 is obtained with reference to the solid line of the map shown in FIG. That is, the solid line in the map of FIG. 4 shows the value that the first smoothed increase value QSMAAC1 should take in correspondence with the accelerator pedal depression speed ΔACP. And the first obtained in this way
Smoothed increase value QSMAA1 and first smoothed increase value QSMA
The final first smoothed increase value QSMA1 is calculated by adding AC1. Next, at step 112, the calculated first smoothing increase value QSMA1 is added to the previous injection amount QBSOL, and the result is set as the basic injection amount QBASE1.

On the other hand, when the idle off time CIDLOF is not within the predetermined time KOF in step 110, the accelerator pedal 57 is further depressed from the state where the accelerator opening ACCP is larger than "0%" to start the acceleration. Then, the process proceeds to step 113. In step 113, the accelerator opening A read previously
Based on CCP and accelerator depression speed ΔACP,
The second smoothed increase value QSMA2 is calculated with reference to the maps shown in FIGS. 3 and 4.

That is, first, based on the accelerator opening ACCP, the second smoothed increase value QSMAA2 is obtained with reference to the broken line of the map shown in FIG. That is, the broken line in the map of FIG. 3 indicates the value that the second smoothed increase value QSMAA2 should take, corresponding to the accelerator opening ACCP. Then, as is apparent from the figure, when the same accelerator opening ACCP is compared, the second smoothed increase value QS
MAA2 becomes a value larger than the first smoothing increase value QSMAA1. Further, based on the accelerator depression speed ΔACP, the second smoothed increase value QSMAAC2 is obtained with reference to the broken line of the map shown in FIG. That is, the broken line in the map of FIG. 4 indicates the value that the second smoothing increase value QSMAAC2 should take in correspondence with the accelerator pedal depression speed ΔACP. Then, as is clear from the figure, when compared at the same accelerator depression speed ΔACP, the second smoothed increase value QSMAAC2 is the first smoothed increase value QS.
The value is larger than MAAC1.

The second smoothed increase value QSMAA2 and the second smoothed increase value QSMAA thus obtained
By adding C2 and C2, the final second smoothed increase value QSMA2 is calculated. Then, this second smoothed increase value QSMA2 becomes a value larger than the first smoothed increase value QSMAAC1 when compared with the same accelerator opening ACCP and accelerator depression speed ΔACP. Next, at step 114, the calculated second smoothing increase value QSMA2 is added to the previous injection amount QBSEOL, and the result is set as the basic injection amount QBASE1.

Thereafter, at step 115, it is judged if the basic injection amount QBASE1 set at the previous step 112 or step 114 is smaller than the fuel injection amount QGOV calculated at step 102. Then, when the basic injection amount QBASE1 is smaller than the fuel injection amount QGOV, in step 116, the basic injection amount QBASE1 is used as it is for the current basic injection amount QBA.
Set as SE. If the basic injection amount QBASE1 is not smaller than the fuel injection amount QGOV, the fuel injection amount QGOV is set as the current basic injection amount QBASE in step 117.

After that, the process proceeds to step 118, and the processes of steps 118 to 120 are executed as already described. That is, as shown in the time charts of FIGS. 5 and 6, the fuel injection amount QGOV calculated on the basis of the accelerator opening ACCP or the like is set as the upper limit value, and the basic injection amount QBASE1 is set to the first or the first fuel injection amount for each control cycle. 2 Normalized increase value QSM
A1 and QSMA2 are gradually increased to perform acceleration smoothing control. Then, the final injection amount QFIN is determined based on the basic injection amount QBASE1, and the fuel injection amount control for the diesel engine 2 is performed.

Particularly, here, the same accelerator opening degree AC
When compared with CP and accelerator pedal depression speed ΔACP, the second average increased value QSMA2 is the first average increased value Q.
The value is larger than SMAAC1. Therefore, when the basic injection amount QBASE1 is increased by the first smoothing increase value QSMA1 as shown in FIG. 5, the basic injection amount QBASE1 is increased by the second smoothing increase value QSM as shown in FIG.
The amount is increased more gently than when the amount is increased by A2. As a result, the time Tn required for the acceleration smoothing control becomes long. On the other hand, the basic injection amount QBASE1 is equal to the second smoothing increase value QSM.
When the amount is increased by A2, the basic injection amount QBASE1
Is increased more quickly than in the case where the value is increased by the first smoothing increase value QSMA1. As a result, the time Tn required for the acceleration smoothing control becomes shorter.

In this way, the moderation control of the fuel injection amount during acceleration is performed. As described above, in this embodiment, as shown in FIG.
When the accelerator pedal 57 is depressed from the state of "0%" to start acceleration, the basic injection amount QBASE1
The acceleration smoothing control is performed so that is increased by the first smoothing increase value QSMA1. On the other hand, as shown in FIG. 6, when the accelerator pedal 57 is further depressed and acceleration is started from a state where the accelerator opening ACCP is larger than "0%", the basic injection amount QBASE1 is the first smoothed increase value. Q
Second smoothing increase value QSMA2 that is larger than SMA1
Acceleration smoothing control is performed so that the amount is increased step by step.

Therefore, at the time of acceleration from a low load state where the accelerator opening ACCP with the largest acceleration shock is "0%", the fuel injection amount is increased relatively slowly, and the time Tn required for the smoothing control is long. Become. That is, the smoothing control with emphasis on the acceleration shock is performed, and as a result, the occurrence of the acceleration shock can be reliably prevented. On the other hand, during acceleration from a state in which the accelerator opening ACCP, where the acceleration shock is less of a problem, is larger than "0%", the fuel injection amount is increased relatively quickly, and the time Tn required for the smoothing control is increased. Becomes shorter. That is, the smoothing control that emphasizes the accelerating property rather than the acceleration shock is performed, and as a result, the lag of acceleration is eliminated and a good acceleration feeling can be secured.

As described above, in the present embodiment, it is possible to surely prevent the occurrence of an acceleration shock at the time of acceleration and to eliminate the rattling of acceleration to secure a good acceleration feeling. .

Further, in this embodiment, the idle switch 7
Idle off time CI based on the on / off state of 3a
Measures DLOF and sets its idle off time CIDLOF
Based on whether or not is within a predetermined time KOF, it is determined whether or not the accelerator opening ACCP before acceleration detection is larger than "0%". Then, as described above, the first or second smoothed increase value QSM is determined by a simple determination as to whether or not the accelerator opening ACCP before acceleration detection is larger than "0%".
Which increase value of A1 and QSMA2 is used to perform the smoothing control is determined. Therefore, the determination operation for determining the smoothing increase value does not become complicated, and there is no risk of malfunction.

The present invention is not limited to the above-described embodiments, and the configurations of the respective parts may be modified and embodied as follows, for example, without departing from the spirit of the present invention.

(1) In the above embodiment, the increase value in the smoothing control is changed based on whether the accelerator opening ACCP before acceleration detection is larger than "0%". A value other than "0%" may be used as the accelerator opening ACCP. For example, the reference accelerator opening A
Set CCP to an opening equivalent to the accelerator opening at which driving force starts to be applied to the vehicle equipped with the diesel engine 2.

(2) In the above embodiment, the amount of increase in the smoothing control is changed based on whether the accelerator opening ACCP before acceleration detection is larger than "0%". The increase value is changed based on whether or not the previous fuel injection amount is larger than the smoothing start injection amount QRL.

(3) The value of the first smoothing increase value QSMA1 or the second smoothing increase value QSMA2 in the smoothing control should be changed appropriately. For example, the accelerator opening AC before acceleration detection
When CP is greater than “0%”, the second smoothing increase value QSMA2 may be a value corresponding to the difference between the previous injection amount QBSOL and the fuel injection amount QGOV. That is,
During acceleration from a state where the accelerator opening ACCP is larger than "0%", the smoothing control is not performed.

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

[0066]

As described above in detail, according to the present invention, when the fuel injection amount or the accelerator opening degree before the acceleration detection is larger than the predetermined value and the acceleration shock is not so serious, the acceleration detection is performed. The previous fuel injection amount or accelerator opening is equal to or less than a predetermined value, and the smoothing control is performed with an increase value larger than that in the case of a low load where acceleration shock becomes a problem. For this reason, it is possible to reliably prevent the occurrence of an acceleration shock at the time of acceleration, and it is possible to eliminate the delay in acceleration and to obtain a good acceleration feeling.

[Brief description of drawings]

FIG. 1 shows an EC in one embodiment embodying the present invention.
4 is a flowchart illustrating a main routine for a fuel injection amount control process executed by U.

FIG. 2 is a flowchart illustrating a main routine for a process of fuel injection amount control, which is also executed by the ECU, in the embodiment.

[FIG. 3] In one embodiment, the first with respect to an accelerator opening degree.
3 is a map in which the second smoothed increase value is predetermined.

FIG. 4 is a map in which first and second anneal increase values with respect to an accelerator pedal depression speed are predetermined in one embodiment.

FIG. 5 is a time chart for explaining the operation of acceleration smoothing control in one embodiment.

FIG. 6 is a time chart for explaining the operation of acceleration smoothing control in one embodiment.

FIG. 7 is a schematic configuration diagram showing a fuel injection amount control device for a diesel engine with a supercharger in one embodiment.

FIG. 8 is a sectional view showing a fuel injection pump in one embodiment.

FIG. 9 is a block diagram showing an electrical configuration of an ECU in one embodiment.

[Explanation of symbols]

1 ... Fuel injection pump, 2 ... Diesel engine, 35 ...
Speed sensor, 57 ... Accelerator pedal, 71 ... ECU,
73 ... Accelerator position sensor, 73a ... Idle switch.

Claims (2)

[Claims] 1. An engine operating state including an engine speed and an accelerator opening is detected, it is determined whether or not acceleration is being performed based on the detected engine operating state, and the diesel engine should be supplied during acceleration. In a fuel injection amount control method for a diesel engine in which the moderation control is performed to gradually increase the fuel injection amount by a predetermined increase value, when the fuel injection amount before acceleration detection or the accelerator opening is larger than a predetermined value A method for controlling a fuel injection amount of a diesel engine, characterized in that the fuel injection amount before acceleration detection or the accelerator opening is smaller than or equal to a predetermined value, the smoothing control is performed with a larger increase value. 2. The fuel injection amount control of the diesel engine according to claim 1, wherein the amount of increase is changed based on whether or not the accelerator opening degree before acceleration detection is larger than 0. Method.