JPH08158912A - Engine speed control device - Google Patents

Abstract

PURPOSE: To suppress engine stalling from occurring and prevent smoke from being produced by controlling a rise in speed based on a start map when an engine speed is below a target start idle speed. CONSTITUTION: An ignition switch 78 detects the start of an engine and, when an engine speed at that time based on the detected results of a speed sensor 35 is below a target predetermined idle speed at starting, ECU 71 obtains a fuel injection amount by the engine speed at that time and a start map set lower than a fuel injection amount obtained usually based on a map. Next a solenoid spill valve 23 is controlled so that the fuel injection amount is reached so as to control the speed so that a target start idle speed is reached. Then, when the target start idle speed is reached, ECU 71 obtains the fuel injection amount for the speed at that time usually from the map based on the detected results of the speed sensor 35, and controls the speed to the target idle speed by an electromagnetic spill valve 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational speed control device for an engine such as a diesel engine, and more specifically, to an engine rotational speed at the time of starting the engine more than a predetermined target idle rotational speed at the time of starting. The present invention relates to an engine speed control device that is configured to raise the engine speed to a value near a target idle speed at start when the engine speed falls.

[0002]

2. Description of the Related Art Conventionally, for example, the rotation speed control at the time of starting a diesel engine is performed as follows. As shown in FIG. 10, an idle map M1 is set in which the injection amount command value τ1 is calculated for the engine speed NE when the accelerator pedal is not depressed. The idle map M1 is set so that the injection amount command value τ1 increases as the engine speed NE decreases. or,
A start-up map M2 is set in which the injection amount command value τ2 is set regardless of the engine speed NE when the starter signal SG is turned on.

Therefore, when the starter is operated to start the engine, the injection amount command value τ2 is obtained in the starting map M2 based on the starter signal SG being turned on.
Then, the injection amount command value τ regardless of the engine speed NE
2 is supplied to the engine. After that, the starter signal SG
When is turned off, the map at the start M2 is shifted to the idle map M1, and the injection amount command value τ1 based on the engine speed NE at that time is obtained. Fuel based on the obtained injection amount command value τ1 is supplied to the engine.

[0004]

By the way, when the engine speed NE reaches the predetermined start target idle speed (in this case, 700 rpm / min) MNE, the starter signal is indicated by a chain double-dashed line. When SG is turned off, the injection amount command value τ1 is determined by the idle map M1.
Is required. At this time, the injection amount command value τ1 is set smaller than the injection amount command value τ2.

However, the turn-off operation of the starter becomes faster,
When the engine speed NE becomes, for example, 400 rpm / min, it becomes lower than the target idle speed MNE. Therefore, the injection amount command value τ based on the idle map M1
1 is set. At this time, since the fuel injection amount based on the injection amount command value τ1 is large, engine stall is prevented, but there is a problem that a large amount of smoke is generated.

As a countermeasure against this, Japanese Patent Laid-Open No. 59-63333.
A combustion control device for a diesel engine shown in Japanese Patent Publication has been proposed. This is because even if the starter is turned off and the engine speed at that time is equal to or less than the target idle speed MNE at the start, the injection amount command value τ2 based on the start map M2 is kept constant and the engine speed NE is When the target idle speed MNE at startup is reached, the idle map M
It is adapted to shift to 1.

In this case, the injection amount command value τ2 is constant and is set smaller than the injection amount command value τ1. Therefore, the fuel injection amount does not become excessive, so that the generation of smoke is suppressed. However, on the contrary, since the actual idle speed NE becomes smaller than the target idle speed MHN, there is a problem that idle vibration occurs or engine stall occurs in some cases.

The present invention has been made in view of the above-described circumstances, and an object thereof is to suppress the generation of a large amount of smoke even when the engine speed at the start is equal to or lower than the target idle speed at the start, and It is an object of the present invention to provide an engine speed control device capable of suppressing the occurrence of idle vibration and engine stall and increasing the engine speed up to a target idle speed at startup.

[0009]

In order to achieve the above object, in the present invention, a rotational speed detecting means for detecting an engine rotational speed of an engine and an amount of fuel injected into the engine are adjusted. When the engine speed of the engine does not reach a predetermined target idle speed based on the detection result of the engine speed adjusting means and the engine speed detecting means, the engine speed of the engine When the fuel injection amount increases, the fuel injection amount is determined based on a normal map set so that the fuel injection amount increases, and the engine speed is controlled so that the fuel injection amount becomes the fuel injection amount. In a rotation speed control device for an engine, which includes a rotation speed control means for controlling the engine speed, a start detection means for detecting the start of the engine and the rotation speed detection device When the engine speed at the time of starting the engine based on the detection result of the means is equal to or lower than the predetermined target start idle speed at the time of start, it is lower than the fuel injection amount obtained based on the engine speed at that time and the normal map. A fuel injection amount is obtained based on the set start-up map, and the rotation adjusting means is controlled so that the fuel injection amount becomes the fuel injection amount, and the engine revolution speed at the start is controlled to the target idle revolution time at the start. The gist is that the number control means is provided.

[0010]

According to the above construction, the starting detection means detects the start of the engine, and the engine speed at that time is equal to or less than the predetermined starting target idle speed based on the detection result of the rotation speed detection means. In this case, the starting rotation speed control means obtains the fuel injection amount based on the starting time map set lower than the fuel injection amount obtained based on the engine rotation speed at that time and the normal map. That is, when the engine speed is equal to or lower than the target idle speed at start, the fuel injection amount obtained by the start map and the engine speed at that time is the fuel injection amount obtained by the engine speed at that time and the normal map. It will be a smaller value. The rotation speed adjusting means is controlled so as to obtain this fuel injection amount, and the engine rotation speed is controlled so as to reach the target idle speed at start.

When the engine speed reaches the starting target idle speed, the engine speed control means, based on the detection result of the engine speed detection means, the fuel injection amount based on the engine speed at that time based on the normal map. Ask. The rotation speed control means controls the rotation speed adjusting means so as to obtain the obtained fuel injection amount, and controls the engine rotation speed of the engine to reach the target idle rotation speed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the engine speed control device according to the present invention is mounted on a diesel engine will be described below with reference to FIGS.
A description will be given based on FIG.

FIG. 1 is a diagram showing a schematic structure of a diesel engine 2 with a supercharger equipped with an engine speed control device of the present embodiment, and FIG. 2 is a sectional view of a distribution type fuel injection pump 1. The fuel injection pump 1 includes a drive pulley 3 drivingly connected to a crankshaft 40 of the diesel engine 2 via a belt or the like. And drive pulley 3
The fuel injection pump 1 is driven by the rotation of, and the fuel is pressure-fed to the fuel injection nozzle 4 provided for each cylinder of the diesel engine 2 to inject the fuel.

A drive shaft 5 is attached to the drive pulley 3.
A fuel feed pump (developed by 90 degrees in the figure) 6 composed of a vane type pump and a disc-shaped pulsar 7 having a plurality of protrusions on its outer peripheral surface are attached to its drive shaft 5. ing. The base end portion (right end portion in the drawing) of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown). Pulsar 7
A roller ring 9 is provided between the cam ring 8 and the cam plate 8, and a plurality of cam rollers 10 facing the cam face 8 a of the cam plate 8 are attached to the roller ring 9. The cam plate 8 is constantly urged and engaged with the cam roller 10 by the spring 11.

A fuel pressurizing plunger 12 is integrally rotatably attached to the cam plate 8, and the rotational force of the drive shaft 5 is transmitted to the cam plate 8 through a coupling, whereby the cam plate 8 is rotated. Also, the plunger 12 is reciprocally driven in the horizontal direction in the figure while rotating. The plunger 12 has a high-pressure chamber 15 between the tip surface (right end surface in the drawing) of the pump housing 12 and the inner bottom surface of the cylinder 14. In the outer periphery of the tip end side of the plunger 12, as many suction grooves 16 as the number of cylinders of the diesel engine 2 are provided.
And a distribution port 17 is formed. Also, the suction groove 16
And the pump housing 13 corresponding to the distribution port 17.
An intake port 19 and a distribution passage 18 are formed in the.

When the fuel injection feed pump 6 is driven based on the rotation of the drive shaft 5, fuel from a fuel tank (not shown) is supplied into the fuel chamber 21 through the fuel injection port 20. Further, in the suction process in which the plunger 12 moves (returns) to the left in the drawing to depressurize the high pressure chamber 15, one of the suction grooves 16 communicates with the suction port 19 and the fuel chamber 21 moves to the high pressure chamber 15 Fuel is introduced into. On the other hand, the plunger 12 moves to the right in the figure (forward movement).
Then, in the compression process in which the high pressure chamber 15 is pressurized, fuel is pressure-fed from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder and injected.

The pump housing 13 has a spill passage 22 for fuel overflow that connects the high pressure chamber 15 and the fuel chamber 21.
Is formed, and an electromagnetic spill valve 23 as a rotation speed adjusting means is provided in the middle thereof. This electromagnetic spill valve 23
Is a normally open valve, and when the coil 24 is in a non-energized (off) state, the valve body 25 is opened and the fuel in the high pressure chamber 15 overflows into the fuel chamber 21. Also, the coil 24 is energized (ON)
As a result, the valve body 25 is closed and the overflow of fuel from the high pressure chamber 15 to the fuel chamber 21 is stopped.

Therefore, by controlling the energization time of the electromagnetic spill valve 23, the electromagnetic spill valve 23 is controlled to be closed / opened, and the overflow of the fuel from the high pressure chamber 15 to the fuel chamber 21 is controlled. . Then, by opening the electromagnetic spill valve 23 during the compression process of the plunger 12, the fuel in the high pressure chamber 15 is decompressed and the fuel injection from the fuel injection nozzle 4 is stopped. That is, the fuel pressure in the plunger 15 does not rise, and the fuel injection from the fuel injection nozzle 4 is not performed. Further, during the forward movement of the plunger 12, by controlling the closing / opening timing of the electromagnetic spill valve 23, the fuel injection amount from the fuel injection nozzle 4 is controlled.

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

The timer device 26 is operated by hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the timer housing 27, and a low pressure chamber 29 on one side of the timer housing 27. The timer piston 28 is composed of a timer spring 31 and the like that presses and urges the timer piston 28 to the pressure chamber 30 on the other side. The timer spring 28 is connected to the roller ring 9 via a slide pin 32.

In the pressurizing chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. The position of the timer piston 28 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 the position of the timer piston 28, and the plunger 12 is inserted via the cam plate 8.
The reciprocating timing of is determined.

In order to control the fuel pressure of the timer device 26, a timing control valve 33 is provided in a communication passage 34 connecting the pressurizing chamber 30 and the low pressure chamber 29. The timing control valve 33 is an electromagnetic valve whose opening and closing is controlled by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by the opening and closing control of the timing control valve 33. Then, the lift timing of the plunger 12 is controlled by the fuel pressure adjustment, and the fuel injection timing from each fuel injection nozzle 4 is adjusted.

A rotation speed sensor 35, which is composed of an electromagnetic pickup coil and serves as a rotation speed detecting means, is mounted above the roller ring 9 so as to face the outer peripheral surface of the pulsar 7. The rotation speed sensor 35 detects passage of the protrusions of the pulsar 7 or the like when they cross each other, and outputs a timing signal (engine rotation pulse) corresponding to the engine rotation speed NE. 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. As shown in FIG. 2, in the diesel engine 2, the cylinder 41, the piston 42, and the cylinder head 43.
A main combustion chamber 44 corresponding to each cylinder is formed. Similarly, the cylinder head 43 is provided with a sub combustion chamber 45 corresponding to each cylinder, and each sub combustion chamber 45 communicates with the main combustion chamber 44. 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.

An intake pipe 47 and an exhaust pipe 50 are connected to the diesel engine 2, a compressor 49 of a turbocharger 48 is arranged in the intake pipe 47, and a turbine 51 of the turbocharger 48 is arranged in the exhaust pipe 50. It is set up. A waste gate valve 52 for adjusting the supercharging pressure is attached to the exhaust pipe 50.

Further, the diesel engine 2 has an exhaust pipe 5
A recirculation pipe 54 is provided for recirculating a part of the exhaust gas in 0 to the intake port 53 of the intake pipe 47. Reflux pipe 54
An EGR valve 55 for adjusting the amount of exhaust gas recirculation is provided in the middle of, and the EGR valve 55 is controlled to open and close by the control of a vacuum switching valve (VSV) 56.

Further, in the middle of the intake pipe 47, there is provided a throttle valve 58 which is opened / closed in association with the depression amount of the accelerator pedal 57. Also, the throttle valve 5
A bypass passage 59 is formed in parallel with 8, and a bypass throttle valve 60 whose opening and closing is controlled by an actuator 63 according to various operating states is provided in the middle of the bypass passage 59.
The actuator 63 is driven by the control of the two VSVs 61 and 62.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above.
3, the timing control valve 33, the glow plug 46, and the VSVs 56, 61, 62 are electrically connected to an electronic control unit (hereinafter simply referred to as "ECU") 71, and the drive timings thereof are controlled by the ECU 71. .

In addition to the rotation speed sensor 35, the following sensors are provided as sensors for detecting the operating state of the diesel engine 2 and the running state of a vehicle equipped with the diesel engine 2. That is, the air cleaner 64
An intake air temperature sensor 72 for detecting the intake air temperature of the air sucked into the intake pipe 47 via an accelerator, an accelerator opening sensor 73 for detecting the accelerator opening ACC corresponding to the load of the diesel engine 2 from the opening / closing position of the throttle valve 58, the intake air An intake pressure sensor 74 for detecting the intake pressure in the port 53,
A water temperature sensor 75 that detects the cooling water temperature THW of the diesel engine 2, a rotation reference position of the crankshaft 40 of the diesel engine 2, for example, a crank angle sensor 76 that detects the rotation position of the crankshaft 40 with respect to the top dead center of a specific cylinder,
A vehicle speed sensor 77 is provided for detecting the vehicle speed (vehicle speed) SPD by turning on / off the reed switch 77b by a magnet 77a provided on the axle.

Further, in addition to the various sensors described above, an ignition switch 78 as a start detecting means for detecting the start of the diesel engine 2 is provided. And
When the key is turned to the start mode in order to start the diesel engine 2, the ignition switch 78 is turned on and the on signal is output. When the diesel engine 2 is started and the key is in the on mode, the ignition switch 78 is turned off and the off signal is output.

In the present embodiment, the rotation speed sensor 3
5, intake air temperature sensor 72, accelerator opening sensor 73, intake air pressure sensor 74, water temperature sensor 75, crank angle sensor 7
6, the vehicle speed sensor 77, the ignition switch 78, and the like constitute a driving state detecting means.

Each of the above-mentioned sensors 3 is provided in the ECU 71.
5, 72 to 77 and a switch 78 are connected respectively. Then, the ECU 71 uses the sensors 35, 72 to 77,
Based on the signal output from the switch 78, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSVs 56, 61, 62, etc. are suitably controlled.

Next, the structure of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 includes a central processing unit (CPU) 79, which constitutes a rotational speed adjusting means, a rotational speed controlling means, and a starting rotational speed controlling means, a read-only memory (ROM) 80 in which a predetermined control program and a map are stored in advance, and a CPU 79. Random access memory (RAM) 81 for temporarily storing operation results and the like, backup RAM 82 for holding prestored data, etc., and a logical operation circuit in which these units are connected to input port 83, output port 84, etc. by bus 85. It is configured.

The intake port temperature sensor 7 is connected to the input port 83.
2, the accelerator opening sensor 73, the intake pressure sensor 74, and the water temperature sensor 75 are connected via the buffers 86, 87, 88, 89, the multiplexer 93, and the A / D converter 94. Similarly, at the input port 83, the rotation speed sensor 35, the crank angle sensor 76, the vehicle speed sensor 77, the ignition switch 78, and the waveform shaping circuit 95.
Connected through. Then, the CPU 79 causes the sensors 35, 72 to 77 to be input via the input port 83.
Also, the detection signal of the switch 78 or the like is read as an input value. In addition, the output port 84 is provided with the respective drive circuits 96, 97, 9
Electromagnetic spill valve 23 via 8, 99, 100, 101
Timing control valve 33, glow plug 46
And VSV56,61,62 grade | etc., Is connected.

Then, the CPU 79 controls the sensors 35 and 72.
~ 77 and the input value read from the switch 78, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSV 56, 61, 62 and the like are suitably controlled.

Further, as shown in FIG. 4, the ROM 80 stores a governor map for calculating a fuel injection amount command value (hereinafter, simply referred to as an injection amount command value) VS as a fuel injection amount with respect to the engine speed NE. There is. That is, when the diesel engine 2 is in the idle state, the normal governor map V1 is stored as a normal map for obtaining the injection amount command value VS corresponding to the engine speed NE at that time.
This normal governor map V1 has a characteristic that the injection amount command value VS is proportionally reduced as the engine speed NE increases.

Further, the injection amount command value VS when the starter is on
The governor map V2 at the time of start for seeking is stored. And the engine speed NE is 600 rpm / mi
Below n, the start-time governor map V2 is stored so that the injection amount command value VS becomes constant regardless of the change in the engine speed NE. The characteristics of the start-time governor map V2 when the engine speed NE is 600 rpm / min or more are stored so as to have the same characteristics as the normal governor map V1.

Further, when the diesel engine 2 is started, a starting-time governor map V3 is stored as a starting-time map for obtaining the injection amount command value VS corresponding to the engine speed NE at that time. Governor map V at this start
3 is the injection command value V as the engine speed NE increases.
It has a characteristic that S decreases proportionally. Further, the injection amount command value VS of the start-up governor map V3 is set lower than the injection amount command value VS of the normal governor map V1, and the reduction rate is smaller than that of the normal governor map V1. And the engine speed NE is 600 rpm /
The characteristics of the starting governor map V3 at min or more are as follows.
It is normally stored so as to have the same characteristics as the governor map V1. Further, the starting target idle speed MNE1 and the target idle speed MNE2 in this embodiment are 600.
It is set to ˜800 rpm / min and stored in the ROM 80.

Further, as shown in FIG. 5, the ROM 80 stores first to third governor maps V4 to V6 for obtaining the injection amount command value VS with respect to the engine speed NE.
The first and second bagana maps V4 and V5 show the injection amount command value VS when the engine speed NE0 becomes a predetermined value.
It is a map provided to change the. In this embodiment, when the engine speed NE is less than NE0, the injection amount command value VS is obtained based on the first governor map V1 and the engine speed NE. In this embodiment, the injection amount command value VS determined by the first governor map V4 is constant even if the engine speed NE changes.

Further, when the engine speed NE is NE0 or more, the injection amount command value VS is obtained based on the second governor map V2 and the engine speed NE. The second governor map V2 is set so that the injection amount command value VS decreases as the engine speed NE increases.

Further, the third value is calculated based on the accelerator opening ACC.
One of the governor maps V6 is selected, and the injection amount command value VS is set based on the engine speed NE at that time and the selected third governor map V6. That is, when the vehicle speed SPD of the diesel engine 2 is constant and does not change, the third governor map V6 is used when lowering the vehicle speed SPD.

Next, the operation and effect of this embodiment configured as described above will be described. 6 to 9 show a "fuel injection amount calculation main routine" executed when the injection amount command value VS is calculated among the respective processes executed by the CPU 79, and the predetermined time (for example, 50 ms). ) It is executed by a scheduled interrupt.

First, in step 101, the CPU 79 calculates the engine speed NE of the diesel engine 1 based on the detection signal from the speed sensor 35. Next, at step 102, the accelerator opening sensor 73
The accelerator opening degree ACC is calculated based on the detection signal from. Then, in step 103, the CPU 79 performs integral calculation processing at the time of starting or to obtain the target idle speeds MNE1 and MNE2 to obtain a correction value NEO for learning ISC (idle speed control).

In step 104, the CPU 79
Determines whether the starter is on or off based on the output signal from the ignition switch 78. Then, when the ON signal is output from the ignition switch 78, the CPU 79 proceeds to step 105. Then, in step 105, the CPU 79 stores the flag FA in the RAM 81 as “1”. next,
In step 106, the CPU 79 causes the start-time governor map V2 corresponding to the engine speed NE at that time.
Is compared with the injection amount command value VS based on the normal governor map V1.

The CPU 79 determines the engine speed N at that time.
When it is determined that the injection amount command value VS based on the starting governor map V2 corresponding to E is smaller than the injection amount command value VS based on the normal governor map V1, the CPU 79 selects the starting governor map V2 in step 107. This is because the engine speed NE is 700 rpm / m
If it is not less than in, the normal governor map V1 is selected, and if the engine speed NE is less than 700 rpm / min, the start-time governor map V2 is selected.

Next, as shown in FIG.
, The CPU 79 determines the engine speed NE at that time.
An appropriate injection amount command value VS is calculated based on That is,
The CPU 79 first obtains the injection amount command value VS based on the engine speed NE at that time and the first and second governor maps V4, V5, and selects the smaller one of the obtained injection amount command values VS. Next, the CPU 79 instructs the injection amount command value VS selected based on the engine speed NE and the starting governor map V2 at that time and the injection amount command determined based on the first and second governor maps V4 and V5. Value V
Compare with S and select the larger one. Furthermore, CPU79
Was selected earlier, and the first and second governor V4, V
5. Compare the injection amount command value VS obtained from the starting governor map V2 with the injection amount command value VS obtained based on the third governor map V6, and select the smaller one.

The CPU 79 always performs this comparison process,
Normally, the starting governor map V2 is selected, the engine speed NE at that time, the starting governor map V
2. The injection amount command value VS is calculated based on the accelerator opening degree ACC and the correction value NEO.

Next, at step 109, the injection amount command value VS and the maximum injection amount V S obtained based on the engine speed NE at that time and the selected maps V1 to V6.
Compare with SM and select the smaller injection amount command value. The maximum injection amount command value VSM is a limit injection amount that suppresses smoke, exhaust temperature, etc., and is stored in the ROM 80 in advance.

Then, in step 110, the CPU
Reference numeral 79 controls the electromagnetic spill valve 23 based on the selected injection amount command values VS and VSM to control the injection amount command value. On the other hand, in step 104, when the ignition switch 78 outputs the off signal from the ignition switch 78, the CPU 79 proceeds to step 111 as shown in FIG. In step 111, C
The PU 79 determines whether the flag FA is "1". If the flag FA is "1", the CPU 79 determines that the engine is starting, and proceeds to step 112. If the flag FA is "0", the CPU 79 indicates that the engine is idle.
79 makes a judgment and moves to step 115 which will be described later.

In step 112, the CPU 79 determines whether or not the actual engine speed NE is smaller than a value obtained by subtracting a predetermined amount X previously set from the target start idle speed MNE1 set at this time. Then, the actual engine speed NE is the target idle speed M at the time of starting.
If it is not smaller than the value obtained by subtracting the predetermined amount X from NE1, the engine speed NE at that time reaches the starting idle speed MNE1, and it is assumed that there is no risk of engine stall, and the routine proceeds to step 114 described later. or,
When the actual engine speed NE becomes smaller than the value obtained by subtracting the predetermined amount X from the start target idle speed MNE1, the engine speed NE at that time reaches the start target idle speed MNE1. If there is a risk of engine stall etc., step 11
Move to 3. Then, in step 113, the CP
U79 selects governor map V3 at start-up, step 1
Move to 08.

Next, in step 108, the CPU 7
9 calculates an appropriate injection amount command value VS based on the engine speed NE at that time. That is, the CPU 79 first
The injection amount command value VS is calculated based on the engine speed NE at that time and the first and second governor maps V4, V5, and the smaller one of the calculated injection amount command values VS is selected.
Next, the CPU 79 instructs the injection amount command value VS selected based on the engine speed NE and the starting governor map V3 at that time and the injection amount command determined based on the first and second governor maps V4 and V5. The value VS is compared and the larger one is selected. Further, the CPU 79 has been selected previously, and the first and second governor maps V4 and V5, the governor map V at the time of starting
The injection amount command value VS obtained by 3 and the injection amount command value VS obtained based on the third governor map V6 are compared and the smaller one is selected.

The CPU 79 always performs this comparison process,
Normally, the starting governor map V3 is selected, and the injection amount command value VS is calculated based on the engine speed NE at that time, the starting governor map V2, the accelerator opening ACC, and the correction value NEO.

Next, at step 109, the injection amount command value VS and the maximum injection amount V S obtained on the basis of the engine speed NE at that time and the selected maps V1 to V6.
Compare with SM and select the smaller injection amount command value.

Then, in step 110, the CPU
Reference numeral 79 controls the electromagnetic spill valve 23 based on the selected injection amounts VS and VSM to control the fuel injection amount. If the actual engine speed NE is not smaller than the value obtained by subtracting the predetermined amount X from the target start idle speed MNE1 at step 112, the engine speed N at that time is determined.
Since E has reached the idle speed MNE1 at the time of starting, and there is no fear of engine stall, etc., the routine proceeds to step 114.

As shown in FIG. 9, in step 114, the CPU 79 sets the flag FA to "0", and then proceeds to step 115. In step 115, the CPU
79, the normal governor map V1 is selected and step 108 is selected.
Move to

Next, in step 108, the CPU 7
9 calculates an appropriate injection amount command value VS based on the engine speed NE at that time. That is, the CPU 79 first
The injection amount command value VS is calculated based on the engine speed NE at that time and the first and second governor maps V4, V5, and the smaller one of the calculated injection amount command values VS is selected.
Next, the CPU 79 is selected on the basis of the engine speed NE and the normal governor map V1 at that time, and the injection amount command value VS and the injection amount command value VS obtained from the first and second governor maps V4 and V5. And select the larger one. Further, the CPU 79 uses the first and second selected previously.
The injection amount command value VS and the third governor map V obtained on the basis of the governor map V4, V5 and the normal governor map V1.
The injection amount command value VS obtained based on 6 is compared and the smaller one is selected.

Although the CPU 79 always performs this comparison process,
Normally, the normal governor map V1 is selected, and the injection amount command value VS based on the engine speed NE, the starting governor map V1, the accelerator opening ACC and the correction value NEO at that time are selected.
Is calculated.

Next, at step 109, the injection amount command value VS and the maximum injection amount command value VSM obtained on the basis of the engine speed NE at that time and the selected maps V1 to V6 are compared, and they are smaller. One of the injection amount command values is selected.

Then, in step 110, the CPU
Reference numeral 79 controls the electromagnetic spill valve 23 based on the selected injection amounts VS and VSM to control the fuel injection amount. Further, in step 106, when the injection amount command value VS obtained based on the starting governor map V3 is larger than the injection amount command value VS obtained based on the starting governor map V1, the process proceeds to step 115. Then, the same processing as described above is performed.

Therefore, in order to start the diesel engine 2, an ON signal is output from the ignition switch 78, and the engine speed NE at that time is 700 rpm /
If it is not more than min, the CPU 79 selects the start-time governor map V2, and based on the engine speed NE and the start-time governor map V2 at that time, the injection amount command value V
Calculate S.

Thereafter, when the engine speed NE at that time does not reach the target idle speed MNE1 at start, it is determined that an engine stall occurs, and the CPU 79 selects the governor map V3 at start, and the engine speed NE at that time is selected. And the injection amount command value VS is calculated based on the starting governor map V3.

At this time, since the injection amount command value VS of the starting governor map V3 is set to be larger than the injection amount command value VS of the starting governor map V2, the engine speed NE increases. When the engine speed NE reaches the starting target idle speed MNE1, it is determined that there is no risk of engine stall, and the CPU 79 selects the normal governor map V1.

Then, the CPU 79 calculates the injection amount command value VS based on the engine speed NE at that time and the normal governor map V1, and controls so that the engine speed NE becomes the target idle speed MNE2.

Therefore, the engine speed N at the time of starting
When E does not reach the target idle speed MNE1 at startup, it is considered that the engine may stall, and the engine speed NE is controlled based on the startup governor map V3. At this time, the starting governor map V3 is set to be higher than the starting governor map V2 and lower than the normal governor map V1.

As a result, the engine speed NE can be reliably increased, and moreover, the starting governor map V is higher than the injection amount command value VS based on the normal governor map V1.
Since the injection amount command value VS based on 3 is set lower, the excessive supply of fuel is suppressed, and the large amount of smoke can be reliably suppressed.

The present invention is not limited to the above embodiment, but may be modified as follows. (1) In this embodiment, only one governor map V3 at the time of starting is set. In addition to this, a plurality of starting-time governor maps V3 corresponding to changes in intake air temperature, cooling water temperature, fuel temperature, etc.
May be set, and the injection amount command value VS may be obtained by selecting an appropriate starting governor map V3 in accordance with changes in intake air temperature, cooling water temperature, and fuel temperature.

(2) Although each of the maps V1 to V6 has the characteristic of being a straight line, it may be a curve. (3) In step 112 in the above embodiment, the actual engine speed NE is the start target idle speed M
Although it is determined whether or not it is less than the value obtained by subtracting the predetermined amount X from NE1, the engine speed NE and the start target idle speed MNE1 are not taken into consideration without considering the predetermined amount X.
You may make it compare with.

(4) In the above-described embodiment, the diesel engine 2 having the turbocharger 48 is embodied, but it may be embodied in the diesel engine having the supercharger or the diesel engine 2 having no supercharger. You can also

(5) In the above embodiment, the idle speed control of the diesel engine 2 is embodied, but it may be embodied in a gasoline engine. (6) The transmission (transmission) in the above embodiment may be an automatic transmission or a manual transmission.

Next, technical ideas other than the claims, which are understood from the above embodiment, will be described below together with their effects. (1) In the engine speed control device according to claim 1, the engine is a diesel engine. According to this configuration, since the engine speed at the time of starting the engine can be appropriately controlled, it is possible to prevent the occurrence of smoke and the occurrence of engine stall.

[0071]

As described above in detail, according to the present invention, when the engine speed is equal to or lower than the target idle speed at start, the engine speed is controlled to increase based on the map at start. , It has an excellent effect of suppressing the generation of engine stall and suppressing the generation of a large amount of smoke.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an idle speed control device for a diesel engine according to an embodiment.

FIG. 2 is an enlarged sectional view showing a fuel injection pump.

FIG. 3 is a block diagram showing an electrical configuration of an ECU and the like.

FIG. 4 is a characteristic diagram showing various governor maps.

FIG. 5 is a characteristic diagram showing various governor maps.

FIG. 6 is a flowchart showing a “fuel injection amount calculation main routine” executed by the ECU.

FIG. 7 is a flowchart showing a “fuel injection amount calculation main routine”.

FIG. 8 is a flowchart showing a “fuel injection amount calculation main routine”.

FIG. 9 is a flowchart showing a “fuel injection amount calculation main routine”.

FIG. 10 is a characteristic diagram showing a conventional map.

[Explanation of symbols]

2 ... (Diesel) engine, 23 ... Electromagnetic spill valve as rotation speed adjusting means, 35 ... Rotation speed sensor as rotation speed detecting means, 71 ... Rotation speed adjusting means, rotation speed controlling means, and starting rotation speed controlling means ECU, 78 ... Ignition switch as starting detection means, MNE1 ... Target idle speed at startup, MNE2 ... Target idle speed, NE ... Engine speed, V1 ... Normal governor map as normal map, V3 ... Map at startup Governor map at startup, VS ... Fuel injection amount command value as fuel injection amount

Claims (1)

[Claims] 1. A rotation speed detecting means for detecting an engine rotation speed of an engine, a rotation speed adjusting means for adjusting an engine rotation speed of the engine by adjusting a fuel injection amount to the engine, and the rotation speed. When the engine speed of the engine does not reach the predetermined target idle speed based on the detection result of the detection means, based on the normal map set so that the fuel injection amount increases when the engine speed of the engine decreases. In the engine speed control device, the fuel injection amount is obtained by controlling the engine speed adjusting means to obtain the fuel injection quantity and controlling the engine speed to a target idle speed. A starting detection means for detecting the start of the engine; and an engine speed at the time of starting the engine based on a detection result of the rotation speed detection means. When the engine speed is equal to or lower than the target idle speed specified at startup, the fuel injection amount is calculated based on the startup map set lower than the fuel injection amount calculated based on the engine speed at that time and the normal map. Controlling the rotation adjusting means so that the fuel injection amount is obtained,
An engine speed control device comprising: a starting speed control means for controlling an engine speed at a start to a target idle speed at a start.