JPH01271626A - Device for controlling fuel injection quantity of diesel engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a deceleration shock by lessening the reducing quantity of a fuel quantity according to a control means when a fuel quantity at the time of the previous injection stroke is judged to be a corresponding quantity to a driven operating condition further than when judged to be a corresponding quantity to a driving operating condition, at the time of decelerating an engine. CONSTITUTION:At the time of decelerating a Diesel engine M1, a control means M4 outputs a command for reducing a feeding fuel quantity to a fuel injecting means M3. At this time, a judging means M5 judges whether the fuel quantity commanded by the control means M4 at the time of previous injection stroke is a corresponding quantity to a driving operating condition above a fuel quantity corresponding to a minute load condition in the vicinity of the no-load operation of the engine M1, or a corresponding quantity to a driven operating condition below the fuel quantity corresponding to the minute load condition. When the fuel quantity at the time of the previous injection stroke is judged to be the corresponding quantity to the driven operating condition, a restricting means M6 is operated so as to lessen the reducing quantity of the fuel quantity according to the control means M4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection amount control device for a diesel engine that is effective for reducing deceleration of fuel injected into a diesel engine.

[Prior Art] Generally, a diesel engine has a high compression ratio and therefore has a large mechanical loss, and therefore generates a large negative torque during deceleration operation, resulting in a so-called deceleration shock phenomenon. Therefore, as a technique for preventing such a deceleration shock phenomenon, for example, the following techniques have been proposed. In other words, (1) A diesel engine control device that controls the degree of deceleration by setting a predetermined limit value on the rate at which the amount of fuel injected during deceleration decreases, so as not to cause discomfort or discomfort due to sudden deceleration. ” (Japanese Unexamined Patent Publication No. 57-28829).

(2) When smoothing the fuel injection amount or accelerator opening, the allowable change amount is calculated based on the engine cooling water temperature,
Diesel engine fuel injection amount changes in response to at least one of the following: vehicle speed, transmission shift position, engine speed, and accelerator opening amount to prevent acceleration/deceleration shocks over a wide range of driving conditions. Smoothing control method”
(Japanese Unexamined Patent Publication No. 19943/1983).

(3) Depending on the elapsed time after the start of acceleration/deceleration, the allowable amount of change in fuel injection amount or accelerator opening is changed to perform appropriate smoothing processing according to the acceleration/deceleration state, reducing acceleration/deceleration shock. "An engine fuel injection amount smoothing control method" (Japanese Patent Application Laid-Open No. 60-32961).

[Problems to be Solved by the Invention] However, in the prior art, when reducing the deceleration, there is a problem in that the relationship between the driving force output by the diesel engine and the occurrence of the deceleration shock phenomenon is not equally considered. In other words, in general, the driving force output by the diesel engine is greater than the load from the start of deceleration to the minute load state near the no-load operating state of the diesel engine. Shock phenomenon is unlikely to occur. On the other hand, if the diesel engine is decelerated further from a very small load state near the no-load operating state, the load becomes greater than the driving force output by the diesel engine, and the diesel engine shifts to a driven state, a so-called engine braking state. Therefore, if the deceleration reduction is not performed appropriately, a deceleration shock phenomenon may occur or a state where engine braking performance cannot be achieved will result. However, in the conventional technology, the deceleration reduction of the fuel injection amount is performed by distinguishing between the case where the diesel engine decelerates from the start of deceleration to a minute load state near the no-load operating state, and the case where the diesel engine further decelerates from the minute load state. There wasn't. Therefore, the control accuracy of fuel injection amount control during deceleration and reduction was low and still insufficient.

In addition, due to inappropriate deceleration reduction control, it is not possible to effectively reduce the driving force within a range that does not cause any adverse effects on the required driving force. There is also the problem that it is not possible to achieve both good engine braking performance and suppression of deceleration surge phenomena.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection control device for a diesel engine that prevents the occurrence of a deceleration shock phenomenon during deceleration, and also appropriately achieves engine braking performance and avoids a deceleration surge phenomenon.

[Means for Solving the Problems] The present invention, which has been made to achieve the above object, as illustrated in FIG. , the amount of fuel commanded from the outside is supplied to the diesel engine M1.
a fuel injection means M3 for supplying fuel to the diesel engine M3;
Based on the change in the fuel amount determined according to the operating state detected by the operating state detecting means M2 in synchronization with the first injection stroke,
A fuel injection amount control device for a diesel engine, further comprising: a control means M4 that outputs a command to reduce the amount of fuel to be supplied to the fuel injection means M3 when the diesel engine M1 is decelerating; When the engine M1 is decelerating, the amount of fuel commanded by the control means M4 during the previous injection stroke is an amount equivalent to the driving operation state, which is equal to or more than the amount of fuel corresponding to a minute load state near the no-load operation state of the diesel engine M1. a determination means M5 for determining whether the amount of fuel in the previous injection stroke is equal to or less than the amount of fuel corresponding to the driven operation state, which is less than the amount of fuel corresponding to the minute load condition; A limiting means M6 for reducing the amount of fuel reduced by the control means M4 when it is determined that the amount is equivalent to the driving operation state than when it is determined that the amount is equivalent to the driving operation state. The gist of this paper is a fuel injection amount control 11 device for a diesel engine.

[Function] The fuel injection amount control device for a diesel engine of the present invention has a first
As illustrated in the figure, the diesel engine M1
When the engine is decelerating, the control means M4 outputs a command to reduce the amount of fuel to be supplied to the fuel injection means M3. During deceleration of the diesel engine M1, the determining means M5:
The amount of fuel commanded by the control means M4 during the previous injection stroke is an amount equivalent to a driving operation state that is greater than or equal to the amount of fuel corresponding to a minute load condition near the no-load operation condition of the diesel engine M1, or the amount of fuel is equivalent to a minute load condition in the vicinity of the no-load operation condition of the diesel engine M1. It is determined whether the amount corresponding to the driven driving state is less than the corresponding fuel amount. Here, when the determination means M5 determines that the fuel amount during the previous injection stroke is an amount equivalent to the driven operation state, and when the limiting means M6 determines that the amount of fuel during the previous injection stroke is the amount equivalent to the driven operation state. This works to reduce the reduction in fuel amount caused by the control means M4.

In other words, when the diesel engine M1 is decelerated, if the amount of fuel supplied is an amount equivalent to the driving operation state, which is more than the amount of fuel corresponding to a small load state near the no-load operation state, the reduction in driving force will not cause an adverse effect. Therefore, the amount of deceleration is reduced relatively quickly, and when the amount of fuel is less than the amount of fuel corresponding to the minute load condition, which is equivalent to the amount of driven operation, the amount of deceleration is limited to a small amount to suppress a sudden drop in driving force and prevent harmful effects. That's what I do.

Therefore, the fuel injection amount control device for a diesel engine of the present invention works to quickly and smoothly reduce the amount of fuel injected during deceleration without causing any adverse effects due to a sudden decrease in driving force.

The technical problems of the present invention are solved by each component of the present invention acting as described above.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail based on the drawings. FIG. 2 shows a system configuration of a fuel injection amount control device for a diesel engine, which is an embodiment of the present invention.

As shown in the figure, a fuel injection amount control device 1 for a diesel engine includes a diesel engine 2 and a distribution type fuel injection pump 3 that supplies high-pressure fuel to the diesel engine 2.
and an electronic control device (hereinafter simply E) that controls these.
It is composed of C (referred to as J)4.

The diesel engine 2 has a cylinder 11 and a piston 12.
A main combustion chamber 13 is formed from the main combustion chamber 13, and a sub-combustion chamber 14 is connected to the main combustion chamber 13. A nozzle 1 for injecting high-pressure fuel pumped from the fuel injection pump 3 is provided in the sub-combustion chamber 14.
5. Glow plug 16 that preheats intake air when starting or when cold
is installed.

In addition, the intake system of the diesel engine 2 is mechanically connected to a compressor 19 of a turbocharger 18 disposed on the upstream side of an intake pipe 17, and an accelerator pedal 20a, so that a main intake air whose opening degree corresponds to the amount of accelerator operation is connected. An auxiliary intake crest valve is disposed in the venturi assembly 21, which is an intake passage that bypasses the main intake crest valve 20, and is adjusted by a diaphragm actuator 22 to three stages: fully open, half open, and fully open. It consists of 23.

A first negative pressure switching valve (
Hereinafter, it will simply be referred to as the first VSV. ) 25 and a second negative pressure switching valve (hereinafter simply referred to as the second VSV) 26. The first VSV 25 and the second VSV 26 introduce negative pressure or atmospheric pressure into the first and second diaphragm chambers of the diaphragm actuator 22 under the control of the ECU 4 (7), and control the opening of the sub-intake valve 23. Adjust. ECU4 is the first VSV25 and the second VSV
26 is not energized (OFF), the auxiliary intake throttle valve 23 is fully open, and when the first VSV 25 is energized (ON) and the second VSV 26 is not energized (OFF), the auxiliary intake throttle valve 23 is half open. State, 1st VSV25 and 2nd V
When both SV26(7) are energized (ON), the sub-intake throttle valve 23 is fully open.

On the other hand, the exhaust system of the diesel engine 2 includes a turbocharger installed on the downstream side of the exhaust pipe 27.
Additionally, a waste gate valve 29 is provided to adjust the boost pressure.

The fuel injection pump 3 includes a drive shaft 31 that receives power from a crankshaft (not shown) of the diesel engine 2, a cam plate 32 that rotates in conjunction with the drive shaft 31, and is integrally coupled with the cam plate 32 and rotates in its axial direction. a plunger 33 slidably supported by a cylinder 34 into which one end of the plunger 33 is fitted, a pressurizing chamber 35 formed by one end of the plunger 33 and the inside of the cylinder 34, and an ECU 4.
The fuel control valve 37 cuts off communication between the pressurizing chamber 35 and the low pressure chamber 3a and communicates the pressurizing chamber 35 only with the delivery valve 36 under the control of the fuel control valve 37.

In the fuel injection pump 3, when the drive shaft 31 rotates in synchronization with the rotation of the diesel engine 2, the cam plate 32 and the plunger 33 rotate, and in the process of the protrusion of the cam plate 32 getting on and off the cam roller of the roller ring 3, the plunger 33 retreats in the axial direction inside the cylinder 34 and sucks the fuel in the low pressure chamber 3a into the pressurized v35. On the other hand, the plunger 33 cylinder 34
When the fuel enters the interior and the fuel control valve 37 is turned off (ON) by a control signal from the ECU 4, the fuel inside the pressurizing chamber 35 begins to be pressurized. The position of the roller ring 38 is
Timing control valve 3 that operates under the control of
9 to perform fuel injection timing control. The pressurized fuel is delivered to the delivery valve 3 until the fuel control valve 37 is turned off (OFF) by a control signal from the ECU 4.
6. In this way, fuel injection amount control is performed by switching the fuel control valve 37 based on the control of the ECU 4. Note that the delivery valve 36 is connected to the fuel vibrator 15.
Each air nozzle 15 of the diesel engine 2 through a
It is connected to the.

The diesel engine fuel injection amount control device 1 includes, as detectors, an accelerator sensor 41 that detects the operating amount of the accelerator pedal 20a, an intake air temperature sensor 42 that detects the intake air temperature inside the intake pipe 17, and a downstream side of the venturi assembly 21. An intake pressure sensor 43 that detects the intake pipe pressure, an ignition timing sensor 44 that detects the ignition timing by receiving light emitted by ignition inside the sub-combustion chamber 14 with a phototransistor, and a water temperature sensor 45 that detects the temperature of the cooling water of the diesel engine 2.
, an electromagnetic pickup type rotation speed sensor 46 for detecting the rotation speed of the drive shaft 31 of the fuel injection pump 3, that is, the rotation speed of the diesel engine 2; , a crank angle sensor 47 for detecting a reference crank angle.

The detection signals of each of the above sensors are manually input to the ECU4, and the ECU
4 controls the diesel engine 2 and the fuel injection pump 3.

The ECU 4 is configured as a logic operation circuit mainly including a CPU 4a, a ROM 4b, a RAM 4c, and a backup RAM 4d, and is connected to an input/output section 4f via a common bus 4e to perform human output with the outside.

The detection signals of each of the above sensors are sent to the CPU via the human output section 4f.
On the other hand, the CPU 4a operates through the human output section 4f to the first VSV 25, the second VSV 26, and the fuel control valve 37.
, timing control valve 39, glow plug 1
A control signal is output on the 4th to activate the glow relay 6.

Next, the fuel injection amount control process executed by the ECU 4 will be described with reference to flowcharts shown in FIG. 3, and the sub-intake throttle valve control process shown in FIG. 4.

First, the fuel injection amount control process will be explained according to the flowchart shown in FIG. This fuel injection amount control process is executed in synchronization with the injection stroke of the diesel engine 2 upon activation of the ECU 4. First, in step 100, a process of reading the accelerator operation amount ACCP and the rotational speed Ne is performed. In the subsequent step 110, a process is performed to calculate the fuel injection amount Q(i) according to the accelerator operation amount ACCP and the rotational speed Ne according to a predetermined map or arithmetic expression. Next, the process proceeds to step 120, where it is determined whether or not the currently calculated fuel injection amount Q(i) is greater than or equal to the previously calculated fuel injection amount Q(i-1), and if an affirmative determination is made, the process proceeds to step 190. On the other hand, if the determination is negative, the process proceeds to step 130. Fuel injection amount Q calculated this time
(i) is decreased from the previous time, that is, in step 130 executed during deceleration, the previously calculated fuel injection amount Q(i-1) is the fuel injection equivalent to the no-load torque operating state for the diesel engine alone. It is determined whether the amount is equal to or greater than the amount QTO, and if the determination is affirmative, the process proceeds to step 140, while if the determination is negative, the process proceeds to step 150. Here, the fuel injection amount QT corresponding to the no-load torque driving state is
O does not simply mean that the accelerator operation amount ACCP is 0, but means a fuel injection amount that allows the diesel engine 2 to maintain the current rotational speed Ne by itself. It should be noted that the fuel injection amount QTO corresponding to the no-load torque operating state is not a constant value; for example, the rotational speed Ne etc.
This is an amount that changes depending on the operating state of the vehicle. Therefore, E.C.U.
In the ROM 4b of No. 4, predetermined operating conditions such as rotational speed Ne and fuel injection amount Q corresponding to the no-load torque operating condition are stored.
A map or calculation formula that defines the relationship with TO is stored, and the ECU 4 determines the fuel injection amount corresponding to the no-load torque driving state to be used in step 130 based on such a map or calculation formula. Calculate QTO.

When the previously calculated fuel injection amount Q(i-1) is greater than or equal to the fuel injection amount QTO corresponding to the no-load torque operating state, that is, the diesel engine 2 is in a driving operating state in which the driving torque output is larger than the load torque. In step 140, which is sometimes executed, the previously calculated fuel injection amount Q(i
-1), a relatively large weight loss value of 3.0 [mm3/s
t/time] and calculates the current fuel injection amount Q(i), the process proceeds to step 160. - On the other hand, when the previously calculated fuel injection amount Q(i-1) is less than the fuel injection amount QTO corresponding to the no-load torque operating state, that is, when the driving torque output by the diesel engine 2 is smaller than the load torque. In step 150, which is executed during the operating state, the previously calculated fuel injection amount Q(i
-1) to a relatively small weight loss value of 0.7 [mm3/s
t/time] and calculates the current fuel injection amount Q (i), the process proceeds to step 160. In step 160, a process of setting the deceleration reduction control flag FD to the value 1 is performed. In the subsequent step 170, control is performed to set the timing at which the injection stroke for injecting the current fuel injection amount Q(i) calculated in either step 140 or step 150 ends in a conveyor register (not shown) inside the ECU 4. Processing to output a signal is performed. Through the process of step 170, the fuel control valve 37, which had been set to the energized state (ON) based on the detection signal of the crank angle sensor 47, is turned to the de-energized state (OFF) at the end of the injection stroke.
) and fuel injection ends. Next step 1
Proceeding to 80, in preparation for the next process, the currently calculated fuel injection amount Q (i) is changed to the previously calculated fuel injection amount Q (i-1).
After performing the process of setting the fuel injection amount, the present fuel injection amount control process ends.

On the other hand, in step 190, which is executed when the currently calculated fuel injection amount Q (i) is increasing in step 120, that is, when the time is not deceleration, the deceleration reduction control flag FD is reset to the value 0. After processing the
The above steps 170 and 180 are executed, and then the present fuel injection amount control process is ended. Thereafter, this fuel injection amount control process repeats steps 100 to 180 in synchronization with the injection stroke of the diesel engine 2.

Next, the sub-intake valve control process will be explained according to the flowchart shown in FIG. This sub-intake valve control process is performed by the ECU
4 is started, it is executed repeatedly every 8[m5ec]. First, in step 2°O, the accelerator operation amount AC
Processing to read the CP is performed. In the following step 210, it is determined whether or not the accelerator pedal 20a is depressed. If the determination is affirmative, the process proceeds to step 260, and if the determination is negative, the process proceeds to step 220. In step 220, which is executed when the accelerator pedal 20a is not depressed, it is determined whether the deceleration/reduction control flag FD is set to the value 1, and if an affirmative determination is made, the process proceeds to step 230; Step 24
0, respectively.

In step 230, which is executed during the deceleration reduction control, the count value of the elapsed time counter CT that measures the elapsed time after the end of the deceleration reduction control is reset to the value 0, and then the process proceeds to step 260. On the other hand, in step 240, which is executed when the deceleration reduction control is not in progress, the process proceeds to step 250 after adding a value of 1 to the count value of the elapsed time counter CT. In step 250, it is determined whether the count value of the elapsed time counter CT is equal to or greater than the value 250. If the determination is affirmative, the process proceeds to step 270, and if the determination is negative, the process proceeds to step 260. In step 260, which is executed when the count value of the elapsed time counter CT is less than the value 250, that is, when more than 2 [sec] have not yet elapsed after the end of the deceleration reduction control, the sub-intake valve 23 is fully opened. The first VSV25 and the second VSV
After performing the process of outputting SV26, the main sub-intake valve control process ends.

On the other hand, in step 270, which is executed when the count value of the elapsed time counter CT is equal to or greater than 250 in step 250, that is, when 2 [sec] or more have passed after the end of the deceleration reduction control, the elapsed time counter CT is A process is performed to limit the count value to the value 250. Next step 28
At 0, after a process of outputting a control signal for half-opening the sub-intake valve 23 to the first VSV 25 and second VSV 26, the main sub-intake valve control process is ended.

From then on, the main sub-intake valve control process is performed every 8 [m5ec].
The above steps 200 to 280 are repeatedly executed.

In this embodiment, the diesel engine 2 corresponds to the diesel engine M1, the accelerator sensor 41 and the rotational speed sensor 46 correspond to the operating state detection means M2, and the fuel injection pump 3 and the nozzle 15 correspond to the fuel injection means M3. . Further, among the ECU 4 and the processing executed by the ECU 4, steps (100 to 120, 170) function as a control means M4, step (130) as a determination means M5, and steps (140, 150) as a restriction means M6. .

As explained above, according to this embodiment, during deceleration, while the fuel injection amount Q (i-1) at the previous injection is equal to or greater than the fuel injection amount QTO corresponding to the no-load torque driving state, a relatively large reduction is achieved. If the value is set to 3.0 [mm3/s t/times] and the fuel injection amount decreases below QTO, a relatively small reduction value of 0
．． A two-stage deceleration reduction is performed that limits the fuel injection amount to 7 [mm”/s t/times], and the fuel injection amount is not suddenly reduced to avoid a sudden decrease in torque during deceleration, so there is no deceleration shock associated with the start of deceleration. In addition to preventing the phenomenon from occurring, it is also possible to suppress the occurrence of idling, which gives the occupants a sense of discomfort.

Furthermore, when the fuel injection amount Q (i-1) at the previous injection decreases to less than 070, which corresponds to the no-load torque driving state, the deceleration reduction value is limited to a small value, so the fuel injection amount Q (i ), it is possible to suppress the deceleration surge phenomenon caused by the decrease in torque associated with the reduction in torque, and to achieve sufficient engine braking performance. That is, as shown in the timing chart of FIG. 5, when the accelerator operation amount ACCP is decelerated from the maximum value (main intake valve fully open state), the vehicle longitudinal acceleration of this embodiment (shown by a solid line in the figure) is There is little change in G over time, and moreover, it attenuates quickly with the passage of time. Therefore, the deceleration surge phenomenon is sufficiently suppressed. However, the time period of vehicle longitudinal acceleration G during so-called no-control (indicated by a dashed line in the figure), in which fuel injection amount is not decelerated and reduced and fuel injection is interrupted in accordance with the operation of the accelerator operation amount ACCP. The changes are large and do not converge easily over time. Therefore, a large deceleration surge phenomenon occurs that gives a sense of discomfort to the occupants. By the way, when decelerating, the conventional technology (
It is shown by a broken line in the same figure. ) The temporal change in vehicle longitudinal direction acceleration G is larger than in this example, and the attenuation is also slower. Therefore, the deceleration surge phenomenon has not yet been sufficiently suppressed.

In this way, the fuel injection amount Q(i) during deceleration is compared with the fuel injection amount QTO corresponding to the no-load torque operating state of the diesel engine 2 to limit the deceleration reduction value, so the fuel injection amount during deceleration is reduced. The control accuracy of control '+8 is increased.

Furthermore, in this embodiment, since the fuel injection amount Q(i) is gradually reduced even during deceleration, the fuel injection amount Q(i) is not cut at the same time as deceleration. Therefore, during deceleration reduction control, the main intake valve 2
0 is in the fully open state, the execution of the sub-intake crest valve control process prevents the auxiliary intake crest during accelerator operation, during deceleration/reduction control of the fuel injection amount, and until 2 [sec] has elapsed after the end of the deceleration/reduction control. The valve 23 is fully opened to ensure a sufficient amount of intake air. Therefore, generation of black smoke and white smoke due to deterioration of the combustion state of the diesel engine 2 can be prevented, and exhaust characteristics during deceleration and weight loss can be maintained favorably.

In this embodiment, the fuel injection amount Q(i) during deceleration is compared with the fuel injection amount QTO corresponding to the no-load torque operating state of the diesel engine 2, and the deceleration reduction value is changed into two stages. However, for example, when comparing the fuel injection amount Q(i) during deceleration with the fuel injection amount QR/L corresponding to the steady running load torque operating state of the diesel engine 2 and the fuel injection amount QTO corresponding to the no-load torque operating state, The deceleration reduction value may be divided into three stages and may be configured to be gradually reduced. With this configuration, it is possible to realize fuel injection amount control during deceleration that is more suitable for the driving condition.

Further, in this embodiment, during deceleration, when the fuel injection amount Q(i-1) at the previous injection is equal to or greater than 070, which corresponds to the no-load torque driving state, the reduction value is set to a relatively large value 3. O [
mm3/s t/times], and set the three-way fuel injection amount QT.
When decreased below 0, the weight loss value is reduced to a relatively small value of 0.7
[It was configured to be limited to mm3/s t/times. However, for example, the reduction value is the fuel injection amount Q(i
-1) is the fuel injection amount equivalent to the no-load torque operating state of 0.
Even if the predetermined reduction value is determined to satisfy the relationship that the value decreases when the fuel injection amount QTO is reduced for a value between 70 or more, the same effect as in this embodiment can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not equally limited to these embodiments, and it goes without saying that it can be implemented in various forms without departing from the gist of the present invention. .

1 bean school! As described in detail above, the fuel injection amount control device for a diesel engine of the present invention is capable of driving a diesel engine in which the amount of fuel supplied during deceleration of the diesel engine is greater than or equal to the amount of fuel corresponding to a minute load state near a no-load operating state. When the amount of fuel is equivalent to the operating state, the decrease in driving force does not have any adverse effects, so the deceleration amount is reduced relatively quickly, and when the amount of fuel is equivalent to the driven operating state, which is less than the amount of fuel corresponding to the minute load state, the deceleration amount is reduced. It is configured to restrict the driving force to suppress a sudden drop in the driving force and prevent harmful effects. For this reason, during deceleration, the amount of fuel supplied is reduced to two levels: a predetermined constant reduction and a limit reduction that is further smaller than the predetermined reduction.
The amount is reduced in stages and the driving force is reduced within a range that does not cause any adverse effects on the required driving force, thereby preventing the occurrence of deceleration shock, providing sufficient engine braking performance that does not give a feeling of running idle, and deceleration surge. This has an excellent effect of optimally suppressing the phenomenon.

In addition, since the amount of fuel during deceleration is compared with the amount corresponding to the driving operation state, which corresponds to the amount of fuel corresponding to a minute load state near the no-load operation state of the diesel engine, and the amount of fuel is reduced, the amount of fuel injected during deceleration is reduced. Quantity control accuracy is dramatically improved.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram conceptually illustrating the contents of the present invention, Fig. 2 is a system configuration diagram of an embodiment of the present invention, Fig. 3,
FIG. 4 is a flowchart showing the control, and FIG. 5 is a timing chart showing the control. Ml...Diesel engine M2...Operating state detection means M3...Fuel injection means M4...Control means M5...Judgment means M6...Limiting means 1...Fuel injection amount control of the diesel engine Device 2... Diesel engine 3... Fuel injection pump 4... Electronic control unit (ECU) 4a"... CPU 15... Nozzle 41... Accelerator sensor 46... Rotational speed sensor

Claims (1)

[Scope of Claims] 1. Operating state detection means for detecting the operating state of the diesel engine; fuel injection means for supplying the diesel engine with an amount of fuel commanded from the outside; When the diesel engine is decelerating, based on the change in fuel amount determined according to the operating state detected by the operating state detection means,
A fuel injection amount control device for a diesel engine, comprising: a control means for outputting a command to the fuel injection means to reduce the amount of fuel to be supplied; The amount of fuel commanded by the diesel engine is either an amount equivalent to the driving operation state that is greater than or equal to the amount of fuel corresponding to a minute load state near the no-load operation state of the diesel engine, or an amount of fuel that is less than the amount of fuel that corresponds to the minute load state of the diesel engine. a determining means for determining whether the amount of fuel in the previous injection stroke is equivalent to the driven driving state; A fuel injection amount control device for a diesel engine, comprising: limiting means for reducing the reduction in fuel amount by the control means when it is determined that there is a fuel injection amount.