JP2540876B2 - Diesel engine speed controller - Google Patents

Description

The present invention relates to a rotational speed control device for a diesel engine, and particularly to a rotational speed control for a diesel engine that performs learning control of a fuel injection amount correction value at times other than idle. Regarding the device.

[Prior Art] Conventionally, as a rotation speed control device at the time of idle of a diesel engine, a basic fuel injection amount is obtained from a reference relationship between an idle target rotation speed determined from detection values of various sensors and a fuel injection amount, and an actual rotation speed is obtained. The fuel injection amount command value is repeatedly obtained by repeatedly correcting the basic fuel injection amount with the cumulative value of the correction amount that is repeatedly obtained based on the difference between the idle target rotation speed and the idle target rotation speed. There is known a device for adjusting the diesel engine to a predetermined target rotational speed by repeatedly controlling fuel injection based on the above (Japanese Patent Laid-Open Nos. 57-70925 and 57-181940).

The cumulative value of the correction amount obtained by the rotation speed control device at the time of idling includes the characteristics of the fuel injection pump of the diesel engine. The fuel injection amount (command value) is set in consideration of the cumulative value. On the contrary, in the exhaust gas recirculation (hereinafter also referred to as EGR) control, the cumulative value of the correction amount is conversely removed from the fuel injection amount command value in order to determine an appropriate EGR rate.

By the way, when the vehicle equipped with the automatic transmission switches the drive range from the drive range to the neutral range when the vehicle is decelerating, etc., even when not idle, the amount of fuel injection is drastically reduced, causing an undershoot of the engine speed. The engine stall may occur and the engine stall may occur below the idle target rotation speed in some cases. Due to other causes, the engine rotation speed may fall below the idle target rotation speed during deceleration or the like, causing an engine stall.

Therefore, when the actual rotation speed is lower than the target rotation speed during idling, the cumulative value of the correction amount obtained during idling is calculated and updated. As a result, the correction amount cumulative value is increased and the fuel injection amount is increased by the amount that the actual rotation speed is decreased, so that the undershoot can be prevented.

[Problems to be Solved by the Invention] However, since the actual rotation speed is lower than the target rotation speed under the condition of calculating the above-mentioned accumulated value except when the engine is idle, it is shown in the timing chart of FIG. 16 (a). like,
Initially, it is controlled based on the governor pattern that is appropriately corrected by the correction amount cumulative value obtained at the time of idling, and even if the actual rotation speed Ne almost matches the target rotation speed NIDL, in reality, it is slightly Hunting and constantly fluctuating above and below the target rotation speed NIDL. Therefore, if the cumulative value of the correction amount is calculated simply under the condition that the actual rotation speed Ne is lower than the target rotation speed NIDL (corresponding to the period tG), the fuel injection amount is always corrected in the direction of increasing the rotation speed. Despite the normal rotation speed, as shown in FIG. 16 (b), the desired rotation speed (in this case, NID
L) will rise.

As described above, since the cumulative value is related to various controls, if the cumulative value rises after being gradually accelerated in the creep running or once in the deceleration state, the cumulative value above the driver's accelerator operation amount may be exceeded. The output was done.
Further, in the above EGR control, the EGR rate is set to a relatively large value, which causes a problem such as smoke.

Configuration of the Invention Accordingly, the present invention has the object of solving the above problems, and has adopted the following configuration.

[Means for Solving Problems] That is, the gist of the present invention is, as illustrated in FIG. 1, a reference of an idle target rotational speed of the engine M1 and a fuel injection amount when the diesel engine M1 is idle. The basic fuel injection amount is obtained from the physical relationship, and the basic fuel injection amount is repeatedly corrected by the cumulative value of the correction amount repeatedly obtained based on the difference between the actual rotation speed and the target rotation speed, and the fuel injection amount command value is repeated. Idle rotation speed control means M2 for determining and controlling the injection of fuel repeatedly based on the fuel injection amount command value that is repeatedly obtained and adjusting the diesel engine M1 to a predetermined target rotation speed, and the accelerator when the diesel engine M1 is not idle. The fuel injection amount is obtained from the reference relationship between the operation amount, the rotation speed of the engine M1, and the fuel injection amount, and the cumulative value of the correction amount is added to this fuel injection amount. In a diesel engine rotation speed control device including injection control means M3 for controlling fuel injection based on the fuel injection amount command value, the rotation speed of the engine M1 is set to the idle target rotation speed other than during idle. From the lower limit rotation speed obtained by subtracting a predetermined value from the determination means M4, and if the determination means M4 determines that the rotation speed of the engine M1 is lower than the lower limit rotation speed, the actual rotation speed And, the idle target rotation speed or the lower limit rotation speed, the cumulative value of the correction amount repeatedly obtained based on the difference between the addition of the correction amount cumulative value obtained by the idle rotation speed control means M2 A diesel engine rotation speed control device comprising: a cumulative value updating means M5 for updating a cumulative value.

[Operation] The idle speed control means M2 is a diesel engine
When the M1 is idling, a basic fuel injection amount is determined from a reference relationship between the target engine speed and the fuel injection amount required for the idling. Next, based on the difference between the actual rotation speed, which is the actual engine rotation speed caused by the intersection / characteristics of the fuel pump, and the target rotation speed, the fuel injection amount is accurately realized or the fuel corresponding to the load is applied. In order to realize the injection amount, the correction value of the basic fuel injection amount is repeatedly obtained and accumulated. The basic fuel injection amount is repeatedly corrected with the accumulated value of the correction amounts to repeatedly obtain a fuel injection amount command value. The fuel injection is repeatedly controlled based on the repeatedly determined fuel injection amount command value to adjust the diesel engine M1 to a predetermined target rotational speed.

In addition, the injection control means M3 is used when the diesel engine M1 is not idle, for example, when it is for an automobile, when the vehicle is running, the fuel injection amount is determined from the reference relationship between the accelerator operation amount, the rotation speed of the engine M1 and the fuel injection amount. Is obtained, and the desired output is realized by controlling the fuel injection based on the fuel injection amount command value obtained by adding the cumulative value of the correction amount to this fuel injection amount.

On the other hand, the determination means M4 determines whether the rotation speed of the engine M1 is lower than the lower limit rotation speed obtained by subtracting a predetermined value from the idle target rotation speed except when the engine is idle.

The cumulative value updating means M5 determines the difference between the actual rotation speed and the idle target rotation speed or the lower limit rotation speed when it is determined by the determination means M4 that the rotation speed of the engine M1 is lower than the lower limit rotation speed. The cumulative value of the correction amount repeatedly obtained based on the above is added to the cumulative value of the correction amount obtained by the idle rotation speed control means M2, and the value is updated.

The predetermined value used in the determination means M4 is, for example, a value that represents the maximum fluctuation range or the average fluctuation range of the rotation speed of the diesel engine M1 during normal operation.

As a result, the minimum value of the engine speed can be maintained near the target speed even when the engine is not idle.

Here, the cumulative value of the correction amount may be the fuel injection amount corresponding to the rotation speed difference, or the rotation speed difference itself. That is, any parameter may be used as long as it is reflected in the fuel injection amount.

Next, examples of the present invention will be described. The present invention is not limited to these, and includes various embodiments without departing from the scope of the invention.

[Embodiment] FIG. 2 is a system configuration diagram of a diesel engine rotation speed control device according to an embodiment of the present invention.

The diesel engine distributed fuel injection pump 1 is driven by the rotation of a drive pulley 3 connected to a crankshaft of a diesel engine 2 via a belt or the like, and pressure-feeds fuel to a fuel injection nozzle 4 of the diesel engine 2. A protrusion 5 is provided on the drive pulley 3, and a predetermined crank angle of the diesel engine 2 (in the present embodiment, TDC (top dead center) is determined by using a reference cam angle sensor 7 provided on a pump housing 6 of the fuel injection pump 1. Point)) can be detected. Further, a vane pump 9 which is a fuel feed pump and a pulsar 10 having a plurality of protrusions on the outer peripheral surface are attached to a drive shaft 8 of the fuel injection pump 1 connected to the drive pulley 3, and the tip portion thereof is not shown. It is connected to the cam plate 11 via a coupling.

The cam plate 11 is integrally joined to the plunger 12,
It is rotated according to the rotation of the drive shaft 8. Further, the cam plate 11 is connected to a roller ring 14 positioned by a timer device 13, and is reciprocated in the left-right direction in the drawing by a cam roller 15 attached to the roller ring 14. Therefore, the cam plate 11 and the plunger 12 are rotated and reciprocated by the rotation of the drive shaft 8.

Next, the plunger 12 is connected to the fuel chamber 16 in the pump housing 6.
The fuel is pressurized by the reciprocating motion of the pump cylinder 17, and the fuel is pressure-fed to each cylinder of the diesel engine 2 via the delivery valve 18. That is, a fuel passage 12a corresponding to the number of cylinders is formed at the tip of the plunger 12, and when moving leftward in the figure, the fuel in the fuel chamber 16 is sucked into the pressurizing chamber 17a and rightward in the figure. When moving, the fuel in the pressurizing chamber 17a is pressurized and the fuel is pumped from the distribution port 12b.

On the other hand, from the pump cylinder 17 to the housing 6, a spill port 17b is formed in communication with the pressurizing chamber 17a of the cylinder 17, and is communicated with the fuel chamber 16 via the electromagnetic spill valve 20. The electromagnetic spill valve 20 is operated by opening and closing the needle valve 20a, and when the plunger 12 moves to the right in the drawing, that is, when the fuel pressurized and pumped, the pressurizing chamber 17a communicates with the fuel chamber 16 at a controlled timing, The fuel in the pressurizing chamber 17a overflows and the fuel supply to the diesel engine is stopped. Also, the plunger
The fuel introduction passage 17c of the cylinder 17 communicates with the fuel passage 12a of the cylinder 12, and is opened by the fuel cutoff valve 21 in the suction stroke, and is shut off in other strokes.

Next, the timer device 13 includes a timer housing 13a, a timer piston 13b fitted in the timer housing 13a and connected to the roller ring 14, and a spring 13c for urging the timer piston 13b rightward in the drawing. Composed,
By positioning the timer piston 13b with the fuel pressure in the high-pressure chamber 13d into which the high-pressure fuel in the fuel chamber 16 is introduced, the position of the roller ring 14 is determined, and the fuel injection timing is adjusted. The fuel pressure in the high-pressure chamber 13d is the same as the high-pressure chamber 13d and the low-pressure chamber.
A hydraulic control valve 23 provided in a communication passage 22 for communicating with 13e and controlled to be opened and closed by a pulse drive signal whose duty ratio is controlled.
Is regulated by

A rotation speed sensor that generates a detection signal every time a protrusion formed on the outer peripheral surface of the pulsar 10 crosses the roller ring 14 positioned by the timer device 13 and the hydraulic control valve 23 at a position facing the pulsar 10. And a real cam angle sensor (hereinafter, also referred to as a rotational speed sensor) 25 which is also capable of detecting the rotational speed of the fuel injection pump, that is, the engine rotational speed of the diesel engine 2 and the fuel injection cycle of the fuel injection pump. Have been. That is, this pulsar 10
The outer peripheral surface of the incisor has four parts that divide the outer peripheral surface into four equal parts
Since the 56 projections are formed, a waveform of the detection signal from the actual cam angle sensor 25 is shaped to obtain a reference signal synchronized with the fuel injection cycle and a reference cam angle signal representing the rotation speed. Further, since the actual cam angle sensor 25 is fixed to the roller ring 14 and moves with its rotation, when the cam roller 15 is lifted from the reference signal and the actual cam angle signal,
That is, the fuel injection cycle can be detected from the fuel injection start timing and the start timing. The TDC signal of the diesel engine 2 can be obtained by shaping the detection signal from the reference cam angle sensor 7 described above.

In the diesel engine 2, a main combustion chamber 35 is formed by a cylinder 33 and a piston 34, and a sub-combustion chamber 36 having a glow plug 36a is continuously provided in the main combustion chamber 35. Fuel is injected into the auxiliary combustion chamber 36. In addition, the turbocharger 38 is installed in the intake pipe 37 of the diesel engine 2.
The compressor 39 is provided, while the exhaust pipe 40 is provided with a turbine 41. The exhaust pipe 40 is also provided with a waste gate valve 42 for adjusting the supercharging pressure.

Further, an exhaust gas recirculation passage 45 communicates an intake system downstream of the compressor 39 of the turbocharger 38 and an exhaust system upstream of the turbine 41 of the turbocharger 38. An exhaust gas recirculation control valve 46 for controlling the EGR rate is provided in the middle of the exhaust gas recirculation path 45. The opening of the exhaust gas recirculation control valve 46 is controlled by controlling the negative pressure of the diaphragm chamber 46a. A negative pressure regulating valve 47 regulates and supplies a negative pressure from a negative pressure source to the diaphragm chamber 46a. The adjustment of the negative pressure is controlled by the duty signal.

The detection system is provided in the rotational speed sensor (actual cam angle sensor) 25 of the fuel injection pump 1, the accelerator sensor 51 including a potentiometer for detecting the accelerator operation amount, and the intake pipe 37 of the diesel engine 2 as described above. An intake air temperature sensor 52 for detecting a temperature, and a supercharging pressure sensor 5 disposed at an intake port 37a communicating with the intake pipe 37 and detecting a supercharging pressure.
3, a water temperature sensor 54 provided in the cylinder block 33a to detect a cooling water temperature, a neutral switch 57 indicating that the shift of the automatic transmission is in neutral, and an NS pole of a rotating magnet provided on the axle by turning on / off a reed switch. A vehicle speed sensor 58 that detects the speed of the vehicle instead of the off signal is provided.

The detection signals of the above sensors are electronic control devices (hereinafter simply referred to as EC
U) 60 is entered. On the other hand, the ECU 60 controls the diesel engine 2 from the side of the fuel injection pump 1 by driving the fuel cutoff valve 21, the electromagnetic spill valve 20, and the hydraulic control valve 23, and drives the negative pressure regulating valve 47 to perform EGR. Control the rate,
Further, the glow plug 36a is controlled.

 Next, the configuration of the ECU 60 will be described with reference to FIG.

The ECU 60 inputs and calculates each signal detected by each sensor described above according to a control program, and performs a process for controlling each of the valves 20, 21, 23, 47 and the glow plug 36a by a central processing unit ( Hereinafter, simply referred to as CPU) 60a, read-only memory (hereinafter simply referred to as ROM) 60b in which the above control program and initial data are stored in advance, various data input to the ECU 60 and data necessary for arithmetic control are temporarily stored. Random access memory (hereinafter simply referred to as RAM) 60c to be stored and various data necessary for subsequent control of the diesel engine 1 can be stored and held even if the key switch of the diesel engine 1 is turned off by the driver. Backup random access memory backed up by a battery (hereinafter simply referred to as backup RAM Mainly 60d, etc. is configured as a logic operation circuit performs input and output of the external each device is connected to the input port 60f and the output port 60g through a common bus 60e.

Further, the ECU 60 includes a buffer 60h, 60i, 60j, 60k for the output signals from the accelerator sensor 51, the water temperature sensor 54, the intake air temperature sensor 52, the boost pressure sensor 53, and the neutral switch 57 described above.
60p is provided, and some of the above sensors 51, 52, 53,
A multiplexer 60q that selectively outputs the output signal of 54 to the CPU 60a, an A / D converter 60r that converts an analog signal to a digital signal, a rotation speed sensor (actual cam angle sensor) 25, a reference cam angle sensor 7, and a vehicle speed sensor A waveform shaping circuit 60s for shaping the waveform of the output signal of 58 is also provided. Signals from these sensors are input to the CPU 60a via the input port 60f.

Further, the ECU 60 includes the electromagnetic spill valve 20, the fuel cutoff valve 21, the hydraulic pressure control valve 23, the negative pressure adjustment valve 47, and the glow plug 36 which are already described.
a is provided with a drive circuit 60t, 60u, 60v, 60w, 60x, and the CPU 60a is connected to the drive circuit 60t, 60u, 60v, 60
Output control signal to w, 60x.

Next, the processing executed by the ECU 60 will be described based on the flowcharts shown in FIG.

First, the flow chart of FIG. 4 shows the diesel engine 2
FIG. 5 shows an interrupt routine for calculating the rotation speed of the engine. An interrupt request signal is generated by a pulse signal from a rotation speed sensor (actual cam angle sensor) 25 attached to the injection pump 1, and an interval between pulses shown in the graph of FIG. Is stored in an array variable T (i) (step 100), and the number of data corresponding to one revolution of the engine is cyclically accumulated in the memory (step 110). As a result, data ΔT (i) for one rotation from the most recent rotation data is accumulated, and data past one rotation or more is forgotten.

The flowchart of FIG. 6 shows an interrupt routine for calculating the vehicle speed, in which an interrupt request signal is generated based on the detection signal of the vehicle speed sensor 58, and the time between pulses is set to a variable TSP.
It is stored in D (step 120), and the vehicle speed SPD is calculated from the variable TSPD.
= K1 / TSPD (K1: constant) is calculated (step 130).

Next, the flowcharts of FIGS. 7 and 8 show a fuel injection amount calculation main routine.

First, at step 210, the rotation speed Ne = K2 / ΣT (i) (K2: constant) is calculated from the pulse-to-pulse time data ΣT (i) for one rotation of the engine 2 accumulated in the rotation speed interrupt routine of FIG. , This value is the engine speed. In step 220, the accelerator opening ACC is calculated from the output value from the accelerator sensor 51.

In step 300, a target idle rotation speed (NIDL) according to the operation state is calculated. The flowchart of FIG. 9 shows the target idle rotation speed calculation logic. First, at step 310, the engine coolant temperature THW is calculated. At step 320, the coolant temperature correction coefficient F according to the coolant temperature THW is calculated.
(W) is calculated. This function F (w) has characteristics as shown in the graph of FIG.

Next, at step 330, in the case of a torque converter vehicle, the neutral switch 57 determines whether the range is the neutral (N) range or the drive (D) range. If it is the D range, jump to step 340, and if it is the N range, jump to step 345, and set the target idle speed ND (D range) of each range.
Water temperature correction coefficient F obtained in step 320 to NN (N range)
(W). ND and NN are target rotation speeds in the fully warmed-up state, and when the cooling water temperature is low, the target rotation speed is F
(W), the warm-up idle is increased. Cooling water temperature THW for each range of torque converter
Is set to NF. This NF is set to NIDL in step 370.

Returning to the injection amount calculation routine of FIG. 7, in step 400, the expected governor pattern proportional correction amount (proportional amount) NP due to load changes such as cooling water temperature THW and neutral range is calculated. The flowchart of FIG. 11 shows the logic for calculating the estimated governor pattern proportional correction amount (proportional amount) NP. First, at step 410, a correction amount NPW corresponding to the cooling water temperature THW is calculated. NPW has characteristics as shown in the graph of FIG.

Next, at step 420, the output content of the neutral switch 57 is judged, and if it is the D range, it jumps to step 440, and if it is the N range, it jumps to step 470. In step 440, the governor pattern correction amount constant KN PD (D range), which allows for a load change accompanying the change of the torque converter to the D range, and the cooling water temperature correction amount Npw are added to obtain a new Npw. Then, in step 470, the new Npw is set as the prospective governor pattern proportional correction amount Np.

Returning to FIG. 7, the idle stable state is determined by the determination from step 500 onward to step 550. That is, it is determined by the determination in step 500 whether or not it is in the state after startup (Ne> 400 rpm), and if it is after startup (Ne> 400 rpm), an affirmative determination is made, and in step 510, the accelerator pedal determined in step 220 above. From the opening ACC, it is determined whether or not it is in the idle state. That is, it is determined whether the accelerator opening ACC = 0.
If it is idle, it is judged in step 520 whether or not the vehicle speed SPD is zero, and if it is zero, the routine proceeds to step 530. Step 5
At 30, the elapsed time from when all of the conditions of 500, 510 and 520 are satisfied is counted by a counter CTIME in units of, for example, 5 msec (or 5 to 50 msec). If it is determined in step 550 that 1.5 seconds or more has elapsed, it is determined that the engine is in the idle stable state, and the process proceeds to step 560 and thereafter. If any one of the conditions of steps 500, 510 and 520 is not satisfied, the process proceeds to step 540 and CTIME is cleared. Then, in step 555, it is determined whether the actual rotation speed Ne is less than the lower limit rotation speed (NIDL-ΔNe), including the case where 1.5 seconds or more has not elapsed in the determination in step 550. If it is less than NIDL-ΔNe, in order to prevent the undershoot of the rotation speed, a correction amount calculation step 56 is performed.
0 or less is executed. If it is not less than NIDL-ΔNe, the process jumps to step 790 described later. As the predetermined value ΔNe, the maximum fluctuation range or the average fluctuation range of the rotation speed of the diesel engine 2 in a normal state is experimentally measured in advance. Alternatively, the maximum fluctuation range or the average fluctuation range may be constantly measured and used by the ECU 60 in the idle stable state.

In step 560, which is executed as a stable idle state or a state where there is a possibility of undershoot, (the target idle rotation speed NIDL in step 300 may be calculated here). The target idle rotation speed NIDL obtained in step 300. And the current actual rotational speed obtained in step 210
The difference ΔN IDL from Ne is calculated.

Next, in step 600 of FIG. 8, the governor pattern integration correction amount (integration amount) NI is calculated based on the difference. First
The flowchart of Fig. 3 shows the calculation logic.

First, in step 610, the correction integration amount ΔNI is determined from ΔNIDL by a calculation formula or map interpolation using characteristics as shown in the graph of FIG. 14 (a) or (b).

In step 620, the correction integration amount ΔNI obtained in 610 is added and integrated to obtain ΣΔNI. In the determination in step 630, it is determined whether or not the upper limit value and the lower limit value of the integrated value ΣΔNI in step 620 are deviated (herein, both upper and lower limits are absolute values KN IMAX), and if deviated, step 640 The upper limit (+ KN IMAX) and the lower limit (-KN IMAX) are guarded with. Governor pattern integration correction amount ΣΔNI
Is set to NI in step 650.

Returning to the injection amount calculation routine of FIG. 8, in step 710, the sum of the governor pattern proportional correction amount NP obtained in step 470 and the integral correction amount NI obtained in step 650 is set as the total correction amount NPI.

Next, at step 790, the total correction amount NPI obtained at step 710 is subtracted from the actual rotation speed Ne by the following equation to obtain the fuel injection amount calculation rotation speed value Ne0.

Ne0 = Ne-NPI In step 800, this fuel injection amount calculating rotation speed value N
Based on e0 and the accelerator opening ACC, the final injection amount QFIN is obtained by a map search or a calculation formula. That is, assuming that the fuel injection amount calculation rotation speed value Ne0 is lower than the actual rotation speed Ne a, the governor pattern showing the relationship between the rotation speed and the fuel injection amount in FIG. , The final injection amount QFIN actually obtained is Q0 larger than the injection amount Qa corresponding to the rotation speed Ne a by ΔQPI.

Next, at step 830, the injection amount command signal VS corresponding to the final injection amount QFIN is output to the injection amount control actuator drive circuit.

The fuel injection amount control is performed as described above, and finally the injection amount control is performed based on the value of QFIN.

The present embodiment is configured as described above,
The cumulative value NI of the correction amount is calculated under the idle stable state and the conditions other than the idle, but the condition is Ne <NIDL-
It is ΔNe.

Therefore, even when the rotation speed undershoots at times other than idling, the fuel injection amount increases due to the increase in the cumulative value NI of the correction amount, engine stall is prevented, and
Since the cumulative value NI calculation of the correction amount is started at a value lower than the idle target rotation speed NIDL by the predetermined value ΔNe, the fuel injection amount does not become excessive during creep running or deceleration. For this reason, the rotation speed of the engine can be converged to near NIDL as shown in FIG. 16 (a), so that the phenomenon that the vehicle speed gradually increases can be prevented. In addition, the responsiveness to the accelerator operation amount is maintained constant even during normal traveling, and the EGR control is properly controlled.

In the above embodiment, the electronic control unit 60 corresponds to the idle rotation speed control means M2, the injection control means M3, the determination means M4 and the cumulative value updating means M5, and the fuel injection amount calculation main routine of FIGS. 7 and 8 is executed. Of the steps 210, 220, 300, 400,
The processing of 500,510,520,530,540,550,560,600,790,800,830 corresponds to the processing as the idle rotation speed control means M2,
The process of steps 790, 800 and 830 corresponds to the process as the injection control means M3, the step 555 corresponds to the process as the determination means M4, and the process of steps 560 and 600 corresponds to the cumulative value updating means M5.
Corresponds to the processing as.

In the above embodiment, the governor pattern integral correction amount NI represented by the rotation speed is used as the cumulative value of the correction amount. Instead, the fuel correction amount corresponding to the speed difference is obtained, and the fuel correction amount is accumulated to accumulate the cumulative value. May be used.

EFFECTS OF THE INVENTION As described above, the present invention is effective when the engine is not used at the time of idling.
When it is determined that the rotation speed of M1 is lower than the lower limit rotation speed obtained by subtracting a predetermined value from the idle target rotation speed,
The cumulative value of the correction amount is updated.

Therefore, it is possible to prevent engine stall due to undershoot at times other than idling, and to prevent the fuel injection amount from becoming excessive during creep running or decelerating running, and to prevent the speed from gradually increasing. Further, the responsiveness to the accelerator operation amount is kept constant even during normal traveling, and the EGR control is properly controlled. Therefore, as a side effect, the rotation speed of the engine does not unnecessarily increase, the fuel efficiency is improved, and the braking effect is improved.

[Brief description of drawings]

FIG. 1 is an exemplary diagram of the basic configuration of the present invention, FIG. 2 is a system configuration diagram of an embodiment of the present invention, FIG. 3 is a block diagram of its electronic control unit, FIG. 4, FIG. 6, FIG. 8 and 9,
11 and 13 are flowcharts of the fuel injection amount calculation main routine in the processing executed by the electronic control unit, FIG. 5 is a signal waveform diagram of the rotation speed sensor, and FIG. 10 is a function of cooling water temperature. FIG. 12 is a graph showing the relationship between the estimated governor pattern correction amount and the cooling water temperature, FIG.
Figures (a) and (b) are graphs showing the relationship between the difference between the target rotational speed and the actual rotational speed and the correction integral amount, Fig. 15 is a graph showing the governor pattern, and Figs. 16 (a) and (b) are conventional 3 is a timing chart showing an example engine rotation speed. 1 ... Fuel injection pump, 2 ... Diesel engine 20 ... Electromagnetic spill valve 25 ... Rotation speed sensor (actual cam angle sensor) 38 ... Turbocharger, 47 ... Negative pressure adjustment valve 54 ... Water temperature sensor 57 ... … Neutral switch 58 …… Vehicle speed sensor, 60 …… Electronic control unit

Claims (1)

(57) [Claims] 1. When a diesel engine is idle, a basic fuel injection amount is obtained from a reference relationship between an engine idle target rotational speed and a fuel injection amount, and it is repeatedly obtained based on a difference between an actual rotational speed and the target rotational speed. The fuel injection amount command value is repeatedly obtained by repeatedly correcting the basic fuel injection amount with the cumulative value of the correction amount that is obtained, and the fuel injection is repeatedly controlled based on the fuel injection amount command value that is repeatedly obtained, and the diesel engine is predetermined. Idle rotation speed control means for adjusting to the target rotation speed, and the fuel injection amount is obtained from the standard relationship between the accelerator operation amount, the engine rotation speed, and the fuel injection amount when the diesel engine is not idle. Injection control means for controlling fuel injection based on the fuel injection amount command value to which the cumulative value of the correction amount is added, In the engine rotation speed control device, further, the judgment means for judging that the rotation speed of the engine is lower than the lower limit rotation speed obtained by subtracting a predetermined value from the idle target rotation speed except when the engine is idle, When it is determined that the engine rotation speed is lower than the lower limit rotation speed, the cumulative value of the correction amount that is repeatedly obtained based on the difference between the actual rotation speed and the idle target rotation speed or the lower limit rotation speed, A diesel engine rotation speed control device, comprising: a cumulative value updating means for updating the cumulative value by adding it to the cumulative value of the correction amount obtained by the idle rotation speed control means.