JP3108906B2 - Starter control device for engine working machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control device for an engine, and more particularly to an improvement in a start control device for controlling a start device of an engine to which a working machine is connected.

[0002]

BACKGROUND ART There is an engine working machine in which an engine is connected to a compressor of a pneumatic machine or a hydraulic pump of a hydraulic machine in order to drive a working machine such as a pneumatic machine or a hydraulic machine used for civil engineering. In this type of engine work machine,
The engine is started by a starting device including a drive motor. That is, when the key switch is manually turned from the off position to the starter position, the pinion gear connected to the drive motor meshes with the ring gear connected to the crankshaft of the engine. When the drive motor is driven to rotate the pinion gear, the engine is started via the ring gear. Thereafter, when the key switch is manually returned from the starter position to the ON position, the operating device stops.

If the operation device is stopped by manual operation of the key switch, the drive motor is driven even though the start of the engine is completed. The capacity of the drive motor is wasted, and the drive motor is excessively rotated by the start of the engine, which may cause deterioration or failure of the drive motor. Further, if the key switch is turned to the starter position by mistake after the start of the engine, the starter operates to cause the pinion gear to hit the rotating ring gear, causing a gear noise or damaging the pinion gear or the ring gear.

[0004]

2. Description of the Related Art For this reason, in a conventional engine working machine,
The start control device detects the rotation speed of the engine to determine the completion of the start of the engine. After the start of the engine is completed, the start device is stopped even if the key switch is at the starter position. That is, the conventional start control device determines the completion of the start of the engine by detecting the rotational speed of the engine by the following methods, for example. That is, the power generation voltage of the alternator or dynamo whose voltage increases in response to the increase in the rotation speed of the engine is measured. Then, when the generated voltage of the alternator or the like becomes equal to or higher than a preset voltage (reference value), it is determined that the engine has been started.

As another method, a photo sensor is provided to face a ring gear of an engine. Then, the gear teeth of the ring gear passing through the detection area of the photo sensor with the rotation of the engine are converted into pulse signals and measured, and the number of pulses is set to a predetermined number of pulses per unit time.
When the value is equal to or more than the reference value, it is determined that the engine has been completely started. By the way, when a cold engine is started by stopping the engine for a long time, for example, the rotation speed of the engine rises and reaches a peak immediately after the engine is started to be driven by the starting device as shown in FIG. Before the start of the engine is completed, the engine starts to descend, and thereafter, the engine may be started again after being raised again.

[0006]

In the above-described conventional start control device, it is erroneously determined that the engine has been started at the engine speed increased immediately after the start of the engine drive, and the operating device is controlled before the engine start is completed. May stop. Further, the rotation speed of the engine fluctuates little by little due to the intermittent combustion of the engine. Therefore, the generated voltage of the alternator and the number of pulses from the photo sensor also change in small steps with this small change, and as shown in FIG. 3, the rotation speed of the engine becomes the reference value (800 rpm in FIG. 3).
After the value becomes equal to or more than m), so-called chattering, which is equal to or less than the reference value in a short time, occurs.

[0007] The chattering causes the starting device to repeatedly start and stop, and a rush current repeatedly flows to the drive motor of the start device in a short time. The rush current compares the deterioration and failure of the drive motor. There is a risk of inviting in a short period of time. In addition, in the start control device, when the start of the engine is completed, a start notification signal is sent to the control device of the work implement, and the work implement starts operating after receiving the start notification signal. Due to small fluctuations in the voltage and the number of pulses from the photo sensor,
The start-up notification signal is sent little by little, and the work machine may malfunction.

On the other hand, there is a case where the engine is stopped by returning the key switch to the off position, and then the engine is restarted before the engine cools down. At this time, since the lubricating oil still spreads over the engine, the rotation speed of the engine increases to the high-speed rotation in a short time, and the start of the engine is completed in a short time. At this time, stopping the starting device in a short time can prevent wasteful current consumption after starting the engine. In addition, in a state where the engine is in a no-load state due to improper mounting of the work machine to the engine or an excessive load is applied to the work machine, the engine speed is increased to a high speed and then the engine is stopped.

In this case, the engine is repeatedly stopped even if the starter is operated until the working machine is properly mounted on the engine or an excessive load is released, and the drive motor is driven by the engine rising to a high speed. Is rotated at a high speed, which may cause deterioration or failure of the drive motor in a relatively short period of time. SUMMARY OF THE INVENTION It is an object of the present invention to reduce deterioration and failure of a drive motor of a starting device and prevent a malfunction of a control device of a work implement while reliably starting an engine.

[0010]

[Means for Solving the Problems]

(First invention) In order to achieve the above object, the first invention is to
For example, as shown in FIG. 1, a work implement 2 is connected to an engine 1 so as to be drivable, and a starting device 3 for starting the engine is provided.
And a control means 4 having a comparator 24. A control means 4 having a comparator 24 is provided, and the rotation speed detection means 11 and the reference value setting means 22 are provided to the comparison input of the comparator 24. And the output of the comparator 24 is connected to the input of the start / stop means 29 and the input of the start notifying means 30, respectively, so that the rotation speed of the engine 1 is equal to or higher than the reference value preset by the reference value setting means 22. Then, the rotation increase notification signal is output from the comparator 24 to the start / stop means 29 and the start notification means 30. In response to the rotation increase notification signal from the comparator 24, the start / stop signal is output from the start / stop means 29. The start notifying unit 30 is configured to output a start notification signal from the start notifying unit 30. An engine working machine configured to control the starting device 3 to a stopped state when a signal is output, and to control the working machine 2 to an operable state when a start notifying signal is output from the start notifying unit 30. Is characterized in that it is configured as follows.

That is, the timer 26 is interposed between the output of the comparator 24 and the inputs of the start / stop means 29 and the start notifying means 30, and the output of the timer 26 is connected to the reference value switching means 27 to switch the reference value. The output of the means 27 is connected to the reference value setting means 22, and when the rotation increase notification signal from the comparator 24 continues for a predetermined time T1 or more, the rotation increase notification signal is output from the timer 26, and the reference value switching is performed. The means 27 is configured to decrease the reference value of the reference value setting means 22 according to the rotation increase notification signal from the timer 26.

(Second Invention) According to a second invention, in the first invention, the control means 4 has a second reference value setting means 23, a second comparator 25, and a holding means 28, The means 23 is preset to a second reference value larger than the first reference value of the first reference value setting means 22, and the rotational speed detection means 11 and the second reference value setting means 23 And the output of the second comparator 25 is connected to the input of the start / stop means 29 via the holding means 28. When the rotation speed of the engine 1 is equal to or higher than the second reference value, the second comparator 25 To output a second rotation increase notification signal from the second comparator 25 to the holding means 28, and the holding means 28 outputs the second rotation increase notification signal from the second comparator 25 to the start / stop means 29. Those that are configured to hold the output of the rising broadcast signal.

[0013]

[Action]

(First Invention) In the first invention, for example, as shown in FIG. For example, when the start of the starter 3 is started in order to start the engine 1 which has been cooled by stopping the engine for a long time, immediately after the start of the start of the starter 3 (time t0), the rotation speed of the engine 1 is low, and The rotation speed of the engine 1 detected by the speed detection means 11 is smaller than the reference value of the reference value setting means 22. Therefore, the rotation increase notification signal is not output from the comparator 24, and the rotation increase notification signal is not output from the timer 26 accordingly. Accordingly, the start / stop signal is not output from the start / stop unit 29, the start device 3 continues to operate, the start notification signal is not output from the start notification unit 30, and the work implement 2 does not start operating.

Thereafter, when the rotation speed of the engine 1 increases with the operation of the starting device 3 and the rotation speed of the engine 1 becomes higher than the reference value of the reference value setting means 22 (at time t1), the rotation increases from the comparator 24. Although the notification signal is output, before the set time T1 of the timer 26 elapses, the rotation speed of the engine 1 starts decreasing and becomes smaller than the reference value (t2).
Time). For this reason, the rotation increase notification signal is not output from the timer 26, so that the start / stop signal is not continuously output from the start / stop unit 29, and the start notification unit 30 is not output the start notification signal.

The state in which the rotation speed of the engine 1 starts to increase again and becomes higher than the reference value (at time t3) and becomes higher than the reference value of the rotation speed of the engine 1 is determined by the timer 26.
(Time point t4), the start of the engine 1 has been completed at this time, and the timer 26 outputs a rotation increase notification signal. As a result, a start / stop signal is output from the start / stop means 29 and the starter 3
Is stopped, and the driving of the engine 1 is stopped. Further, a start notification signal is output from the start notification unit 30, and the work machine 2
Operation can be started. In addition, the rotation speed of the engine 1 fluctuates little by intermittent combustion of the engine 1,
As shown in FIG. 3, so-called chattering occurs in which the reference value fluctuates in a short period of time, that is, the chattering period Tc is shorter than the set time T1 of the timer 26, and the output of the timer 26 increases during the chattering. Does not output a notification signal.

On the other hand, in response to the rotation increase notification signal from the timer 26, the reference value switching means 27
After the start of the engine 1 is completed, even if the load on the work implement 2 increases and the rotation speed of the engine 1 decreases (at time t5), the reference value of As long as the value does not become smaller than the reference value, the output of the rotation increase notification signal from the comparator 24 is held, and the output of the start / stop signal from the start / stop means 29 is maintained, whereby the starter 3 does not operate.
In addition, the output of the start notification signal from the start notification unit 30 is also maintained, and the work machine 2 is maintained in a state where it can be continuously operated without interruption.

If the rotation speed of the engine 1 becomes lower than the reference value after the switching due to the stop of the engine 1 or the like, the output of the rotation increase notification signal from the comparator 24 is stopped and the timer 26 The output of the rotation increase notification signal of is stopped. Thereby, the start / stop means 29
Then, the start notifying means 30 is reset, and the starting device 3 returns to the operable state, and the work implement 2 returns to the operation stop state.

(Second Invention) In the second invention, in addition to the above-described operation of the first invention, the following operation is performed. That is, as shown in FIG. 4, for example, when the operation of the starter 3 is started after the engine 1 is stopped and before the engine 1 is cooled (time t10), immediately after this operation, the rotation of the engine 1 is performed in the same manner as described above. The speed is smaller than both the first reference value of the first reference value setting means 22 and the second reference value of the second reference value setting means 23. Therefore, the rotation increase notification signal is not output from the comparators 24 and 25, the starting device 3 continues to operate, and the work implement 2 does not start operating.

On the other hand, since the lubricating oil has been sufficiently lubricated in the engine 1 in the previous operation of the engine 1, the rotational speed of the engine 1 sharply increases, and the engine 1 is turned on in a shorter time than the set time T1 of the timer 26. The rotation speed 1 exceeds the first reference value of the first reference value setting means 22 and further exceeds the second reference value of the second reference value setting means 23 (time t11). Then
A second rotation increase notification signal is output from the second comparator 25 via the holding means 28, and a start / stop signal is output from the start / stop means 29, so that the starter 3 is stopped and the driving of the engine 1 is stopped. Since the output of the second rotation increase notification signal is held by the holding unit 28, the stopped state of the starting device 3 is held unless the holding unit 28 is reset.

[0020]

【The invention's effect】

(First Invention) The first invention has the following effects because it is configured and operates as described above. For example, when starting a cold engine by stopping the engine for a long time, the rotation speed of the engine rises and reaches a peak immediately after the engine is started to be driven by the starting device, and then falls before the start of the engine is completed. After that, the engine may be started again after rising again. Even in this case, if the period during which the engine speed is equal to or higher than the reference value of the reference value setting means does not exceed the set time of the timer, the rotation increase notification signal is not output from the timer, and the start / stop signal is output from the start / stop means. Since the output is not output, it is possible to accurately determine the completion of the engine start without erroneously determining the short-term increase in the rotation speed of the engine immediately after the start of driving of the engine as the completion of the engine start. Therefore, it is possible to accurately determine the stop timing of the starting device and reliably prevent an engine start error.

Further, the reference value of the reference value setting means is decreased according to the output of the rotation increase notification signal from the timer.
After the start of the engine, even if the load on the work implement temporarily increases and the engine speed decreases, the engine speed will be lower than the reference value switched to the lower value, such as when the engine is stopped. As long as the rotation speed is not reduced, the output of the rotation increase notification signal is held. Therefore, the output of the start notification signal from the start notification unit is maintained, and the work machine is maintained in a state in which it can continue to operate without interruption. Thereby, the operation of the work machine can be stably performed without being affected by the fluctuation of the load.

Furthermore, the repetition of the starting and stopping of the starting device can be prevented by the operation of the timer due to the small fluctuation of the rotation speed of the engine due to the intermittent combustion of the engine, so that the inrush current to the drive motor of the starting device can be reduced in a short time. By repeating the flow, it is possible to prevent the drive motor from being deteriorated or broken down in a relatively short time. In addition, since the start notification unit does not output the start notification signal unless the rotation increase notification signal is output from the timer, it is possible to prevent the start of the start notification signal from being sent to the work machine and prevent the work machine from malfunctioning.

(Second Invention) The second invention has the following effects in addition to the effects of the first invention. For example, when the engine is stopped and then restarted before the engine cools down, the rotation speed of the engine rapidly rises immediately after the engine is started to be driven by the starter, and the rotation speed becomes high in a short time. In this case, when it becomes equal to or more than the second reference value of the second reference value setting means,
The second rotation increase notification signal is output from the second comparator, and the starting device stops. In other words, when the engine is started before the engine cools down, the rotation speed of the engine is increased to a high speed in a short time and the start of the engine is completed. Is stopped, it is possible to prevent the capacity of the battery from being wasted, and to prevent the drive motor from rotating at high speed due to the engine rising to high speed, thereby reducing the deterioration and failure of the drive motor.

Further, since the output of the second rotation increase notification signal of the second comparator is held by the holding means, unless the key switch is turned off and the power is shut off to reset the holding means, the starting device is stopped. Is held. In other words, when the engine does not start due to improper installation of the work equipment to the engine or excessive load on the work equipment,
Even if the engine is repeatedly driven by the starting device, the engine does not start, and the drive motor may deteriorate or break down due to the repetition of the high-speed rotation of the drive motor accompanying the above-described increase to the high-speed rotation immediately after the drive of the engine. There is. On the other hand, when the second rotation increase notification signal is output as described above, the stop state of the starting device is maintained unless the holding unit is reset, thereby deteriorating the drive motor due to repeated high-speed rotation of the drive motor. In addition, the holding of the starting device in the stopped state can prompt the operator to cancel the improper installation of the working machine and an excessive load on the working machine.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, a configuration of an engine working machine to which an embodiment of a start control device according to the present invention is applied will be described with reference to FIG. FIG. 1A is an overall schematic configuration diagram of the engine working machine, and FIG. 1B is a circuit diagram of the start control device.

In this engine working machine, as shown in FIG. 1A, a working machine 2 is connected to an engine 1, and
A starting device 3 can be connected to the engine 1. Further, the engine working machine includes a start control device (control means) 4.
The start control device 4 controls driving / stopping of the start device 3 and activation of the work implement 2 via a work control device 7.

A ring gear 10 is operatively connected to a crankshaft (not shown) of the engine 1. A rotation speed detecting means 11 such as a photo sensor or a magnetic sensor is provided in opposition to the gear teeth of the ring gear 10. It is provided. The working machine 2, the starting device 3, the starting control device 4, the working control device 7, and the like are connected to a battery 6 via a key switch 5 and are supplied with power. The alternator (or dynamo) 8 connected to 1 is connected and charged.

Next, each part of the working machine 2 and the starting device 3 will be described in detail. An air machine such as a compressor or a hydraulic machine such as a hydraulic pump is applied to the work machine 2, and the operation of the solenoid valve of the work machine 2 is controlled by the work control device 7. The starting device 3 includes a drive motor 13 such as a DC motor, a magnet switch 14, a pinion gear 15, and the like.

Then, the starting device 3 drives the magnet switch 14 to push out the pinion gear 15 connected to the drive motor 13 toward the ring gear 10 to mesh with the ring gear 10 (see a two-dot chain line diagram in FIG. 1). By driving the drive motor 13 to rotate the pinion gear 15, the ring gear 10 is rotationally driven. Thus, the crankshaft of the engine 1 is driven to rotate. When the gear teeth of the ring gear 10 cross the detection area of the rotational speed detecting means 11 with the driving of the engine 1, the rotational speed detecting means 11 detects the gear teeth of the ring gear 10 and converts the gear teeth into a pulse signal. This pulse signal is output to the start control device 4.

The key switch 5 has a contact piece 16. By inserting a key (not shown) and manually turning the key piece 5, the contact piece 16 can be turned to an OFF position, an ON position, and a starter position. Can be switched in order. When the contact piece 16 is switched from the off position to the on position (the position indicated by the two-dot chain line in FIG. 1), the battery 6 and the AC contact 51 are connected via the contact piece 16 and the battery 6 is started. Power is supplied to the control device 4 and the work control device 7.

When the contact piece 16 is switched from the ON position to the starter position (the position shown by the solid line in FIG. 1), the battery 6, the AC contact 51 and the starter contact 52 are connected via the contact piece 16. Then, in addition to the power supply from the battery 6 to the start control device 4 and the work control device 7, etc., the power is also supplied to the start device 3 via a relay contact S1 of a relay L1 described later. The key switch 5
When the hand is released from the key, the contact piece 16 is automatically returned from the starter position to the ON position by the action of a spring (not shown) or the like. When the contact piece 16 is turned off (not shown), the battery 6 is not connected to either the AC contact 51 or the starter contact 52.

As shown in FIG. 1B, the starting control device 4 is constructed and connected as follows. The start control device 4 outputs the output of the above-described rotation speed detecting means 11 (FIG. 1A) to one of input terminals (comparison input) of comparators 24 and 25 via a filter unit 20 and an FV conversion unit 21. )-. The other input terminal + of the comparator (first comparator) 24 is provided with a low-speed reference value setting means.
The output of (first reference value setting means) 22 is connected to the other input terminal of a comparator (second comparator) 25.
Is connected to the output of the high-speed reference value setting means (second reference value setting means) 23.

The output terminal of the comparator 24 is connected to the inputs of the starting / stopping means 29 and the starting notifying means 30 via a timer 26, and to the input of the reference value switching means 27. An output terminal of the comparator 25 is connected to an input of a start / stop unit 29 via a holding unit 28. Next, details of each part of the start control device 4 will be described. The FV converter 21 is configured to control the rotation speed detecting unit 1 from which noise has been removed by the filter unit 20.
1 is converted to a voltage corresponding to the pulse frequency, and the input signals of the comparators 24 and 25 are
Respectively.

The low-speed reference value setting means 22 includes voltage dividing resistors R1 and R2, a resistor R3, and a Zener diode D1, and divides the Zener voltage of the Zener diode D1 by the voltage dividing resistors R1 and R2 to generate a first voltage. It outputs to the other input terminal + of the comparator 24 as a reference voltage value. The supply voltage + B from the battery 6 is applied to the cathode of the Zener diode D1 via the resistor R3 and the above-described key switch 5 (FIG. 1A).

The high-speed reference value setting means 23 is composed of voltage dividing resistors R4 and R5. The voltage dividing resistors R4 and R5 divide the Zener voltage of the Zener diode D1 and use the divided voltage as the second reference voltage value. Output to the + input terminal. Note that the first reference voltage value and the second reference voltage value are respectively adjusted to voltage values output from the FV converter 21 at a predetermined rotation speed of the engine 1. For example, the rotation speed corresponding to the first reference voltage value is 60
The rotation speed is appropriately selected from a rotation speed range of 0 rpm to 800 rpm, and the rotation speed corresponding to the second reference voltage value is the first rotation speed.
The value is higher than the reference voltage value and is from 800 rpm to 100
The rotation speed is appropriately selected from the range of 0 rpm.

The comparators 24 and 25 are each configured as a contact output type such as an open collector.
The comparator 24 is connected to the F-V conversion unit 21 for input terminal −.
When the output voltage is equal to or higher than the first reference voltage value, the output becomes a low level (rotation increase notification signal). The comparator 25 goes to a low level (a second rotation increase notification signal) when the output voltage of the FV converter 21 input to the input terminal − is equal to or higher than the second reference voltage value of the input terminal +. Note that the comparators 24 and 25 may be configured as a voltage output type.

The input of the timer 26 is a base resistor R1
4 and the output of the comparator 24 via the transistor Q6. When the low level state of the output of the comparator 24 continues for a predetermined time T1 or more, a high level voltage is output and this output is output. It is configured to hold a voltage. In addition, the timer 26
When the output voltage of the FV conversion unit 21 becomes lower than the first reference voltage value and the output of the comparator 24 returns to the high level, and this high level state continues for a predetermined time T2 or more, the output voltage becomes high. It is configured to return from the level to the low level.

The reference value switching means 27 includes an input resistor R6
When a high-level voltage is output from the timer 26, the high-level voltage is received at the base of the transistor Q1 via the input resistor R6, and the transistor Q1 is turned on. Then, when the transistor Q1 is turned on, the input terminal + of the comparator 24 is grounded, and the first reference voltage value to the input terminal + drops to almost 0V. That is, the first reference voltage value is changed to the output voltage value of the FV converter 21 when the rotation speed of the engine 1 is approximately 0 rpm.

Note that the input terminal + of the comparator 24 is
When a resistor is connected between the collector of the transistor Q1 and the transistor Q1 is turned on, the first reference voltage value becomes equal to F− when the rotation speed of the engine 1 is, for example, 100 rpm.
The output voltage value of the V conversion unit 21 may be changed. The holding means 28 includes base resistors R7 and R8.
And the transistors Q2 and Q3. The supply voltage + B of the battery 6 is applied to the emitter of the transistor Q2 via the key switch 5 (FIG. 1A). When the output of the comparator 25 becomes low level, a current flows from the base of the transistor Q2 to the comparator 25 via the base resistor R7, and the transistor Q2 is turned on.

Then, the high-level voltage from the transistor Q2 is applied to the start / stop means 29 and the start notifying means 30.
And output to the transistor Q3. As a result, the transistor Q3 is turned on, the base of the transistor Q2 is grounded, and the transistor Q2
Is kept on. That is, the transistor Q2
Once turned on, the on state is maintained until the key switch 5 is returned to the off position and the supply of the supply voltage + B is stopped.

The start / stop means 29 is provided with an input resistor R9 ·
R10, collector resistance R11, transistor Q4
And the relay L1. The output of the timer 26 is connected to the base of the transistor Q4 via the input resistor R9, and the output of the holding means 28 (collector of the transistor Q2) is connected to the transistor via the input resistor R10. Connected to base of Q4. When the output voltages of the timer 26 and the holding means 28 are both at the low level, the transistor Q4 is turned off and the collector resistance R1
1, the supply voltage + B of the battery 6 is supplied to the relay L1, the relay L1 is turned on, and the relay contact S1 is closed.

On the other hand, when the output voltage of at least one of the timer 26 and the holding means 28 is at a high level, the transistor Q4 is turned on to supply the voltage + B supplied to the relay L1.
Is stopped, the relay L1 is turned off, and the relay contact S1 is opened. As shown in FIG. 1A, the relay contact S1 is interposed between the starter contact 52 of the key switch 5 and the starting device 3, and when the relay contact S1 is closed, the contact piece 16 When the supply voltage + B of the battery 6 is supplied to the starting device 3 via the starter contact 52, the starting device 3 operates.

The start notifying means 30 includes an input resistor R12
, A collector resistor R13, and a transistor Q5. The output of the timer 26 is connected to the base of the transistor Q5 via the input resistor R12. When the output voltage of the timer 26 is at a low level, the transistor Q5 is turned off and outputs a high-level voltage to the work control device 7. On the other hand, when the output voltage of the timer 26 is at a high level, the transistor Q5 is turned on and outputs a low-level voltage to the work control device 7 as a start-up notification signal.

The output of the holding means 28 is connected to the base of the transistor Q4 of the starting and stopping means 29 via only the input resistor R10, whereas the base of the transistor Q5 of the starting notifying means 30 is connected. Further includes an input resistor R directly connected to the base of the transistor Q4.
9 and the input resistor R12, most current flows to the base of the transistor Q4 when the output voltage of the holding means 28 is at a high level, and almost current flows to the base of the transistor Q5. Does not flow,
The transistor Q5 does not turn on. That is, when the output voltage of the timer 26 is at the low level, the transistor Q5 of the start-up notification unit 30 is turned off regardless of the output of the holding unit 28.
(Start-up notification signal) is not output to the work control device 7.

Next, the operation of the engine working machine will be described with reference to FIGS. 2 is a timing chart when the engine 1 is started in a cold state, FIG. 3 is a partially enlarged view of the waveform of the engine rotation speed in FIG. 2, and FIG. It is a timing chart at the time of starting.

In this embodiment, the start of the engine 1 is completed when the rotation speed of the engine 1 is 800 rpm or more, and if the work implement 2 has a normal load, the starting device 3 is turned on after the start of the engine 1 is completed. Even if stopped, the engine 1 does not stop. The first reference voltage value is the value of the engine 1
Is adjusted to the output voltage value of the FV converter 21 when the rotation speed of the engine 1 is 800 rpm, and the second reference voltage value is the FV voltage when the rotation speed of the engine 1 is 1000 rpm.
The output voltage value of the conversion unit 21 is adjusted.

First, the operation when the engine 1 is started in a cold state will be described with reference to FIG. In FIG. 2, the rotation speed of the engine 1 is maintained at 1000 even after the start of the engine 1 is completed.
rpm is maintained. A key is inserted into the key switch 5, and the key switch 5 is manually turned as it is to operate the contact piece 16 from the off position to the starter position (time t0). Then, power is supplied from the battery 6 to the start control device 4, the work control device 7, and the like. On the other hand, at time t0, since the engine 1 is stopped, the FV converter 21
Is lower than the first reference voltage value and the second reference voltage value, and both the outputs of the comparators 24 and 25 become high level.

Therefore, a low-level voltage is output from the timer 26, the relay L1 of the start / stop means 29 is turned on, and the relay contact S1 is closed. Then, the battery 6
, Power is supplied to the starting device 3 via the contact piece 16, the starter contact 52, and the relay contact S1, and the starting device 3 is operated. Thus, the start of the engine 1 is started. Further, the output voltage of the holding unit 28 becomes low level in response to the high-level output of the comparator 25, and the high-level voltage is output from the activation notifying unit 30 to the work control device 7. Accordingly, the work control device 7 receives the high level voltage and controls the work implement 2 not to operate.

On the other hand, after the time point t0, the rotation speed of the engine 1 increases with the operation of the starting device 3, reaches 800 rpm or more at the time point t1, then further increases and then decreases, and at the time point t2. It becomes 800 rpm or less again. The set time T1 of the timer 26 is set in advance so as to be longer than the time from the time point t1 to the time point t2.
For this reason, the output voltage of the FV converter 21 becomes equal to or higher than the first reference voltage value during the time from the time point t1 to the time point t2, and the output of the comparator 24 becomes low level (rotation increase notification signal).
However, since the voltage returns to the first reference voltage value or less again after the time point t2, the output voltage of the timer 26 remains at the low level.

The rotation speed of the engine 1 is t
It starts to rise again from the lowered state after the second time point, and after 800 rpm or more at the time point t3, continues to rise further.
When the time during which the rotation speed of the engine 1 becomes 800 rpm or more becomes equal to or more than the set time T1 of the timer 26 (time t4), the timer 26 outputs a high-level voltage as a rotation increase notification signal. As shown in FIG. 3, the rotational speed of the engine 1 fluctuates little by little due to the intermittent combustion of the engine 1 and immediately exceeds 800 rpm, and immediately thereafter becomes 80 rpm.
The speed becomes 0 rpm or less, and thereafter, becomes 800 rpm or more in a short period of time, so-called chattering occurs. This chattering period Tc is considerably shorter than the set time T1 of the timer 26. For this reason, the output voltage of the timer 26 maintains a low level during the chattering period Tc. Thereby, with the slight fluctuation of the rotation speed of the engine 1,
The operation and stop of the starter 3 are prevented from being repeated little by little, and the rush current to the drive motor 13 is repeatedly and quickly passed, thereby preventing the deterioration and failure of the drive motor 13 from occurring in a relatively short time. it can.

The output of the high-level voltage (rotation increase notification signal) from the timer 26 at the time t4 turns off the relay L1 as a start / stop signal from the start / stop means 29 and opens the relay contact S1. It is. As a result, the power supply to the starting device 3 is cut off, the starting device 3 stops, and the driving of the engine 1 stops. At the time t4, the start of the engine 1 has been completed, and the engine 1 does not stop even if the starter 3 is stopped. That is,
By accurately determining the stop timing of the starter 3, it is possible to reliably prevent the engine 1 from being erroneously started. Thereafter, when the operator releases his / her hand from the key inserted into the key switch 5, the contact piece 16 automatically returns from the starter position to the ON position by the action of a spring or the like.

Also, the high-level output voltage from the timer 26 at the time point t4 outputs a low-level voltage as a start-up notification signal from the start-up notification means 30 to the work control device 7, and the work control device 7 In response to the start notification signal, the operation of the work machine 2 is enabled. On the other hand, in response to the output of the high-level voltage (rotation increase notification signal) from the timer 26 at the time t4, the reference value switching unit 27 sets the first reference voltage value to the comparator 24 so that the rotation speed of the engine 1 becomes approximately 0 rpm. The output voltage is reduced to approximately 0 V corresponding to the output voltage value of the FV converter 21 when the engine is stopped.

Therefore, after the start of the engine 1, the load on the work implement 2 temporarily increases. For example, even if the rotation speed of the engine 1 decreases to 800 rpm or less at time t5, the engine 1 does not stop. The output of the comparator 24 holds a low level. Therefore, the start notifying unit 3
0 to the work control device 7 is a start notification signal (low level)
Is continuously output, and the work control device 7 continues the operation of the work machine 2 without interruption. Thereby, the operation of the work implement 2 can be stably performed without being affected by the fluctuation of the load.

If, for example, the work machine 2 is overloaded at time t6 and the engine 1 is stopped, the output of the comparator 24 is inverted from low level to high level. 26 set times T2
When the above is continued (at time t7), the output voltage of the timer 26 becomes low level, the reference value switching means 27 is reset, and the first reference voltage value of the low speed reference value setting means 22 becomes the rotation speed of the engine 1. Returns to the output voltage value of the FV conversion unit 21 when is equal to 800 rpm. On the other hand, with the inversion of the output voltage of the timer 26 from the high level to the low level at the time point t7, the relay L1 of the start / stop unit 29 is turned on.
Therefore, when the key switch 5 is manually turned and the contact piece 16 is again operated from the ON position to the starter position after the time point t7, the starting device 3 operates.

Next, an operation when the engine 1 is started after the engine 1 is stopped and before the engine 1 is cooled will be described with reference to FIG. That is, when the key switch 5 is manually turned to operate the contact piece 16 from the off position to the starter position.
At ten points, the engine 1 has not yet rotated, and the outputs of the comparators 24 and 25 both go high as described above.

Accordingly, the timer 26 and the holding means 2
8 become low level, the relay L1 of the starting / stopping means 29 is turned on, the relay contact S1 is closed, the starting device 3 is operated, and the high-level voltage is output from the starting notifying device 30 to the work control device. Work machine 2 output to 7
Is controlled to a stop state. On the other hand, the lubricating oil has been sufficiently lubricated in the engine 1 by the previous operation of the engine 1, and as a result, the rotation speed of the engine 1 sharply increases by the operation of the starter 3.

Then, the rotation speed of the engine 1 is reduced to 800 rpm (first speed) in a shorter time than the set time T1 of the timer 26.
(Reference value), and thereafter, at t11, 1000 rpm
When it becomes equal to or more than (the second reference value), the output of the comparator 25 becomes low level (second rotation increase notification signal). Then, the high level voltage is applied from the holding means 28 to the start / stop means 29.
(Second rotation increase notification signal) is output, and this high level output voltage is maintained. As a result, the transistor Q4 of the starting and stopping means 29 is turned on, the relay L1 is turned off, the power supply from the battery 6 to the starting device 3 is stopped, and the starting device 3 is stopped. At this time, the start of the engine 1 has been completed.

On the other hand, as described above, the high-level output voltage of the holding means 28 is not transmitted to the activation notifying means 30, and the high-level output voltage from the activation notifying means 30 to the work control device 7 is maintained. The work machine 2 remains stopped. On the other hand, at the time point t12 when the set time T1 of the timer 26 has elapsed since the rotation speed of the engine 1 became 800 rpm or more due to the completion of the start of the engine 1, a high-level voltage (rotation increase notification signal) is output from the timer 26. Then, a start notification signal (low level) is output from the start notification unit 30 to the work control device 7, and the work machine 2 can be operated.

On the other hand, for example, because an excessive load is applied to the work implement 2, the rotation speed of the engine 1 becomes 800 rpm.
If the engine 1 is stopped at the time t13 before the set time T1 of the timer 26 elapses after the above, the holding unit 28 determines whether the output of the comparator 25 becomes high level with the stop of the engine 1. , And holds a high-level output voltage. Accordingly, the off state of the relay L1 of the starting and stopping means 29 is maintained as it is, and even if the key switch 5 returning to the on position is turned to the starter position again, the starting device 3 does not operate. At the time t13, the output voltage of the timer 26 remains at the low level.
The high-level output voltage from the start notification unit 30 to the work control device 7 is also maintained, and the work implement 2 remains stopped.

When the key switch 5 is returned to the off position, the supply voltage + B of the battery 6 to the holding means 28 stops, the holding means 28 is reset, and the output voltage of the holding means 28 returns to the low level. Thereafter, at time t14, when the key switch 5 is manually turned to operate the contact piece 16 from the off position to the starter position, the relay L1 of the start / stop means 29 is turned on and the starter 3 is operated.

That is, when the work machine 2 is improperly mounted on the engine 1 or an excessive load is applied to the work machine 2, the engine 1
Does not start, the engine 1 is not started even if the driving of the engine 1 is repeated by the starting device 3 and the high-speed rotation of the driving motor 13 of the starting device 3 accompanying the rise to the high-speed rotation immediately after the driving of the engine 1 is performed. Drive motor 13 repeatedly
May deteriorate or break down. Further, the capacity of the battery 6 is wasted. In these cases, the starter 3 is quickly stopped, and the power supply to the work implement 2 and the work controller 7 is stopped, and then the work implement 2 is returned to a normal state, and thereafter, the starter 3 is operated. This protects the starting device 3 and the battery 6. For this reason, when the rotation speed of the engine 1 becomes 1000 rpm or more, the starting device 3 is immediately stopped, and the starting device 3 cannot be operated again unless the key switch 5 is returned to the off position.

As a result, it is possible to reliably prevent the drive motor 13 from deteriorating or malfunctioning due to the repetition of the high-speed rotation of the drive motor 13. An excessive load on the machine 2 can be urged to be released.

The above embodiment can be modified as follows. That is, in the above-described embodiment, the rotation speed of the engine 1 is detected by detecting the gear teeth of the ring gear 10 by the rotation speed detection means 11, but the generated voltage of the alternator (or dynamo) 8 has a low rotation speed of the engine 1. Since the rotational speed is sometimes proportional to the rotational speed, the rotational speed of the engine 1 may be detected by measuring the voltage generated by the alternator (dynamo) 8. Further, the rotation speed of the engine 1 may be detected using a tachometer (engine tachometer) or the like.

It is also possible to configure the start control device 4 with a microcomputer, a memory, or the like, and to program the same operation as the start control device 4 of the above embodiment. Further, it is also possible to configure the start control device 4 with a general-purpose IC, for example, by configuring the holding means 28 of the start control device 4 with a general-purpose latch IC.

In the above embodiment, the start / stop means 29
Although the opening operation of the relay contact S1 of the relay L1 is used as the start / stop signal, the start / stop means 29 may output a low-level voltage to the starter 3 as a start / stop signal. In this case, the starting device 3 is configured to operate with the high-level output voltage from the starting / stopping means 29 and stop at the low-level output voltage by the control device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an engine working machine to which an embodiment of a start control device according to the present invention is applied. FIG. 1 (A) is an overall schematic configuration diagram of the engine working machine, and FIG. It is a circuit diagram of the above-mentioned starting control device.

FIG. 2 is a timing chart when the engine is started in a cold state.

FIG. 3 is an enlarged view of a part of the waveform of the engine rotation speed in FIG. 2;

FIG. 4 is a timing chart when the engine 1 is restarted before it cools down.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Work implement, 3 ... Starting device, 4 ... Start control device (control means), 11 ... Rotation speed detecting means, 22 ... Low speed reference value setting means (first reference value setting means), 23 ... High speed Reference value setting means (second reference value setting means), 24 ... comparator (first comparator), 25 ... comparator (second comparator), 26 ... timer, 27 ... reference value switching means, 2
8 holding means, 29 start-stop means, 30 start-up notification means.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02N 11/08 F02N 15/00

Claims (2)

(57) [Claims] A work machine (2) is connected to an engine (1) so as to be drivable, and a starter (3) for starting the engine is connectable to detect a rotation speed of the engine (1). Control means (4) having rotation speed detecting means (11) and comparator (24)
The output of the rotational speed detecting means (11) and the output of the reference value setting means (22) are respectively connected to the comparison input of the comparator (24), and the output of the comparator (24) is connected to the start / stop means ( 29) and the input of the start notifying means (30), respectively, and the rotational speed of the engine (1) is set to the reference value setting means (2).
When the value exceeds a reference value set in advance in 2), the comparator (24) outputs a rotation increase notification signal to the start / stop means.
(29) and the start notifying means (30). A start / stop signal is output from the start / stop means (29) in response to the rotation increase notification signal from the comparator (24). In addition, the start notifying means (30) is configured to output a start notification signal, and when the start / stop signal is output from the start / stop means (29), the starting device (3) is brought into a stopped state. Control and
When a start-up notification signal is output from the start-up notification means (30), the start-up control device for an engine work machine configured to control the work machine (2) to an operable state. Output and start-stop means
A timer (26) is interposed between the reference value switching means (29) and the input of the activation notifying means (30), and the output of the timer (26) is connected to reference value switching means (27). The output of (27) is used as the reference value setting means.
(22), and when the rotation increase notification signal from the comparator (24) continues for a predetermined time (T1) or more, the timer (26)
The reference value switching means (27) is configured to output the rotation increase notification signal from the timer (26) in response to the rotation increase notification signal from the timer (26).
2) A starting control device for an engine working machine, wherein the starting value is reduced. 2. The starting control device for an engine working machine according to claim 1, wherein said control means (4) comprises a second reference value setting means (23) and a second reference value setting means (23).
The second reference value setting means (23) includes a comparator (25) and a holding means (28). The second reference value setting means (23) sets a second reference value larger than the first reference value of the first reference value setting means (22). The output of the rotational speed detecting means (11) and the output of the second reference value setting means (23) are respectively connected to a comparison input of the second comparator (25), and the second comparator (25)
The output of (25) is connected to the input of the starting and stopping means (29) via the holding means (28), and when the rotation speed of the engine (1) is higher than the second reference value, the second The second rotation increase notification signal is output from the comparator (25) to the holding means (28), and the holding means (28) outputs the second rotation increase notification signal from the second comparator (25). A start control device for an engine working machine, which is configured to output to the start / stop means (29) and to hold the output of the second rotation increase notification signal.