JPS62165541A - Control device for prime mover - Google Patents

Abstract

PURPOSE:To facilitate the starting of a prime mover at the time of cold climate by putting a fluid-pressure cylinder for regulating the fuel feeding quantity in a position where a fixed amount of fuel can be supplied, and then causing the electric power source of a driving controller to be cut off after completion of said operation. CONSTITUTION:When a switch 12 is opened so as to stop an engine 1 for driving an oil hydraulic pump 3, which discharges pressure oil to be used for various operations, a fuel solenoid-valve 9 is changed to a shut-off state, and then, the supply of fuel is interrupted and the engine 1 is caused to stop. In addition, hereupon, an interruption is generated in an electronic device 18 in the control unit 16, and it is judged whether a deviation between a target position signal specified in advance of an oil hydraulic cylinder 5 for driving a throttle lever 1b and its present position signal from a position transducer 10 is within a fixed range or not. And then, when the judgement is 'NO', solenoid valves 7, 8 are controlled to open and close so that the oil hydraulic cylinder 5 is operated until said deviation comes to settle down within the fixed range. Subsequently, the power supply to the electronic device 18 is cut off.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a prime mover in a machine or device in which a hydraulic pump is driven by a prime mover, such as a construction machine or a hydraulically driven vehicle.

[Conventional technology]

Machines and devices that use a prime mover, such as an engine, as a driving source to drive a hydraulic pump, such as a hydraulic pump, and perform a desired work using pressure oil from the hydraulic pump, are well-known machines and devices. In devices, five means are often adopted to control the engine drive using a portion of the pressure oil of the hydraulic pump. Such means will be explained with reference to FIG.

FIG. 4 is a system diagram of a conventional engine control device. In the figure, 1 is the engine, 1a is the governor of the engine 1, 1b is the throttle lever of the engine 1, and 2 is the fuel tank of the engine 1. The throttle lever 1b is operated between a low idle position and a full throttle position F. 3 is a hydraulic pump driven by the engine 1, and its pressure oil is used for various operations. 4 is a setting device that controls the rotation of the engine 1, 5 is a hydraulic cylinder, and 6 is a throttle L.
/ Bar 1blft! This is a connecting rod that connects the piston rod of the pressure cylinder 5. Numerals 7 and 8 are solenoid valves that control the supply of pressure oil from the hydraulic pump 3 to the hydraulic cylinder 5, and 9 is a fuel solenoid valve that connects and disconnects the fuel supply path between the fuel tank 2 and the engine 1.

A position detector 10 is connected to the piston rod of the hydraulic cylinder 5 to detect its position, and outputs a signal according to the detected position. 11 is a power source, and 12 is a switch connected to the power source 11. 13 is a control unit that controls the operation of the hydraulic cylinder 5;

A power supply 11 composed of a power supply stabilizing circuit 14 and an electronic device 15 is connected to the power supply stabilizing circuit 14 and a fuel solenoid valve 9 via a switch 8 . The electronic device 15 operates with a constant voltage output from the power supply stabilizing circuit 14, inputs signals from the setting device 4 and the position detector 10, and controls the opening and closing of the solenoid valves 7 and 8 accordingly.

Next, the operation of this device will be explained. When the switch 12 is closed, the fuel solenoid valve 9 is switched to the conducting position.
Fuel in the fuel tank 2 is supplied to the engine 1. In this state, if you set the setting device 4 to the desired engine speed,
A signal SI corresponding to this is input to the electronic device 15. On the other hand, a signal S corresponding to the current position of the piston rod of the hydraulic cylinder 5 is input from the position detector 10 to the electronic device 15. Since the switch 12 is closed, the electronic device B is input to the power supply stabilizing circuit 14. It is in an operating state when a constant voltage is supplied from the Here, if the signal S1 is a signal corresponding to the piston rond position ffUK of the hydraulic cylinder 5 that positions the throttle lever 1b at a position corresponding to the set rotation speed, the electronic device 15 changes the signal S to the signal S.
The solenoid valve 7.8 is controlled so that the value is equal to 1. That is,
When the solenoid valve 7 is turned OFF and the solenoid valve 8 is turned ON, the piston rod of the hydraulic cylinder 5 moves to the right, and the throttle lever 1b
When the solenoid valve 7 is turned on and the solenoid valve 8 is turned off, the piston rod moves to the left and the throttle lever 1b is turned clockwise. to lower the rotation speed. The position detector 10 outputs a signal S corresponding to the position of the piston rod. When the signals s,, St become equal, the electronic device 15
turns off the solenoid valves 7 and 8, and holds the piston rod, ie, the throttle lever 1b, at that position.

Next, when stopping the engine 1, the setting device 4 is first set so that the throttle lever 1b is in the low idle position. Therefore, 10 revolutions of the engine becomes a low idle. Next, when the switch 12 is opened, the fuel solenoid valve 9 is switched to the cutoff position, and the fuel supply is cut off.
Engine 1 stops. In addition, the power supply stabilizing circuit 14 and the power supply 1
The circuit with 1 is also opened, and there is no output from the electronic device [15. Solenoid valves 7 and 8 are turned off. In this state, the throttle lever 1b is maintained at the low idle position t I l/C.

When starting the engine 1 again, the switch 12 is closed. In this case, since the hydraulic pump 3 is not driven, pressure oil cannot be supplied to the hydraulic cylinder 5. Therefore, even if the setting device 4 is set to the desired rotation speed, the hydraulic cylinder 5 cannot be operated. The throttle lever 1b remains held in the lower idle position. switch 12
When the fuel electromagnetic valve 9 is switched by closing, and fuel is supplied to the engine 1, the engine 1 starts. As a result, the hydraulic pump 3 is driven, the hydraulic cylinder 5 becomes operable, and the throttle lever 1b is rotated from the low idle position I to a position corresponding to the rotation speed set in the setting device 4.

In this way, when starting the engine 1, the engine 1 is started with the throttle lever 1b in the low idle position.

[Problem that the invention seeks to solve]

By the way, when starting the engine 1, especially when starting in cold weather, is there any way to ensure a good start? ,: It is necessary to start the engine 1 by setting the throttle lever 1b to the half-throttle position and increasing the fuel injection amount. However, in the conventional device described above, the engine 1 is always started from the low idle position, as described above, and there is a drawback that smooth and good starting cannot be performed in cold weather or the like.

An object of the present invention is to provide a control device for a prime mover that eliminates the drawbacks of the prior art described above and allows easy starting.
be.

[Means to resolve the issue]

In order to achieve the above object, the present invention provides a prime mover, a hydraulic pump driven by the prime mover, a hydraulic cylinder for adjusting the amount of fuel supplied to the prime mover driven by the hydraulic pump, and a hydraulic cylinder that controls the hydraulic cylinder. do. A drive control unit, characterized in that it is provided with an accumulator, a positioning means for moving the hydraulic cylinder to a predetermined position in response to a stop operation of the prime mover, and a power cutoff means for cutting off the power supply when positioning is completed. [Function] When stopping the prime mover, the stopping operation is detected and the hydraulic cylinder is moved to a preset position using the hydraulic pressure of the accumulator, and when the movement is completed, the power to the drive control section is turned on. Cut off. The above objective can be achieved by setting the hydraulic cylinder at a position where it is easy to start the motor when starting it.

〔Example〕

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 1 is a system diagram of an engine control device according to an embodiment of the present invention. In the figure, parts that are the same as those shown in FIG. 4 are given the same reference numerals, and description thereof will be omitted. Reference numeral 16 denotes a control section of this embodiment, which includes a power supply stabilizing circuit 17 and an electronic device 18 using a microcomputer. Power supply stabilization circuit 1
7 is directly connected to the power supply 11 without going through the switch 12, and the terminal of the switch 12 on the opposite side from the power supply 11 is connected to the electronic device 18. Further, the power supply stabilizing circuit 17 is controlled by a signal from the electronic device 18.
It has become. , 19 is an accumulator connected to the hydraulic cylinder 5, 20 is the hydraulic pump 3 and the accumulator 19
There is a check valve in between.

FIG. 2 is a block diagram of a specific example of the control section shown in FIG. 1. In the figure, the same parts as those shown in FIG. 1 are given the same reference numerals. The power supply stabilizing circuit 17 includes transistors 22,
23. It consists of a 24° Zener diode and a 25.26° resistor. Zener diode 24 is connected to the base of transistor 22, and resistor 25 is connected between the collector and base of transistor 22. Also, transistor 2
The collector of 6 is connected to the base of transistor 220.

The electronic device 18 includes a microcomputer 27 and a NOR circuit 28. It consists of a resistor of 29.30. Microcomputer 27 has terminal NMI.

27T, and performs predetermined calculations and control by applying a constant voltage output from the transistor 22 of the power supply stabilizing circuit 17. The terminal NMI is a terminal that detects a fall in the input voltage and generates an interrupt. Also, terminal 27
T is designed to output a high level when there is no interrupt. The NOR circuit 28 is a microcomputer 27
The output of the terminal 27T of the switch 12 and the voltage of the opposite terminal of the power supply 11 of the switch 12 are input, and its output terminal is connected to the pace of the transistor 26 of the power supply stabilizing circuit 17. Note that this NOR circuit 28 is driven by a power supply circuit separate from the power supply stabilization circuit 17.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG. When the switch 12 is closed and a desired rotation speed is set in the setting device 4, the hydraulic cylinder 5 is driven as described above, and the engine 1 is driven at the rotation speed. Also, the accumulator 19 has a check valve 20.
Pressure oil is supplied from the hydraulic pump 3 via and stored. On the other hand, by closing the switch 12, the power supply stabilizing circuit 17
A constant voltage defined by the Zener diode 24 is output from the microcomputer 27, and the microcomputer 27 is in a state where it can perform predetermined calculations and control using this constant voltage. Furthermore, since the switch 12 is closed, the input signal S at the terminal NMI of the microcomputer 27 is at a high level, and no interrupt occurs. And the signal S...
Since S@ is at a high level, the output of the NOR circuit 28 is at a low level, and the transistor 23 of the power supply stabilizing circuit 17 is in a cutoff state.

When the rotation speed set in the setting device 4 is changed while the engine 1 is running, the output signal s changes, and the microcomputer 27 uses this changed signal s1 and the position detector 10.
Calculate the deviation from the current position signal s1 output from
According to this deviation, a signal S$134 is outputted to control the solenoid valve 7.8 so that the deviation becomes approximately O. Deviation is almost O
Then, the microcomputer 27 turns the solenoid valves 7 and 8 to O.
FF.

Next, when the switch 12 is opened to stop the engine 1, the fuel electromagnetic valve 9 is cut off, the fuel supply is cut off, and the engine 1 is stopped. On the other hand, when the switch 12 is opened, the signal S changes from a high level to a low level due to the 3° resistance, and an interrupt occurs in the computer 27. In this state, the output of the terminal 27T still maintains a high level, so the output of the NOR circuit 28 is a low level, the transistor 23 is cut off, the transistor 22 is conductive, and a constant voltage is applied to the microcomputer 27. Application continues.

When an interrupt occurs as described above, the computer 27 performs an interrupt process as shown in the flowchart of FIG. 3. First, the target position signal S of the hydraulic cylinder 5 is detected. is a predetermined signal s, / (step 111ja). The signals s, / are signals corresponding to the position of the throttle lever 1b to improve the starting of the engine 1, and in the case of this embodiment, are determined to be signals corresponding to the -full throttle position. In addition, if there is no interrupt, the target position signal s0 is taken as the output signal sI of the setting device 4, and a process similar to the process described below is performed, that is, a process that makes the deviation from the current position almost O like the four previous MJICs. K that will be done
Become.

After setting the target position signal s0 to a signal S+' corresponding to a predetermined half-throttle position in step a, the current position signal S is read from the position detector 10 (step b).

Then, it is compared whether the absolute value of the deviation between the signal S and the signal S is greater than a certain small predetermined range D (absolute value) (step C). If it is greater than the predetermined range, the hydraulic cylinder is According to this determination, signals Ss, S are output, and the solenoid valves 7 and 8 are controlled to open and close to move the hydraulic cylinder 5 in the desired direction (the absolute value of the deviation is set to 0). (step e). The movement of the hydraulic cylinder 5 is performed by pressure oil in the accumulator 19. This procedure b % e is repeated until the absolute value of the deviation is less than the desired range.

During such processing, if it is determined in step C that the absolute value of the deviation is less than the desired range, the microcomputer 27
turns off both solenoid valves 7 and 8 (step f). As a result, the hydraulic cylinder 5 holds the throttle lever 1b at the half throttle position and the tosle position. Next, the microcomputer 27 sets the output signal s0 at the terminal 27T to a low level.

In this state, the signals Sw and Sg are at a low level, so the output of the NOR circuit 28 is at a high level.

Therefore, the transistor 23 becomes conductive, so that the base potential of the transistor 22 becomes approximately the ground potential. Therefore, the transistor 22 is cut off, and the power to the microcomputer 27 is cut off. At this time, terminal 27T
becomes high impedance, but the signal S remains at a low level due to the resistor 29, and therefore the power supply stabilization circuit 17 continues to cut off the power.

Next, when the switch 12 is closed to start the engine 1 again, the signal S becomes high level.

The output of the NOR circuit 28 is at a low level, the transistor 23 is turned off, and the transistor 22 is turned on. As a result, a constant voltage is supplied to the microcomputer 27, making it possible to perform calculations and control. At the same time, the fuel solenoid valve 9 is energized, the fuel supply path is opened, and fuel is supplied to the engine 1.

Engine 1 starts to start.

At this time, since the throttle lever 1b is at the predetermined half throttle position in the engine stop control, more fuel can be injected than in the low idle position, so even in cold weather. The engine 1 can be started easily.

Although the above embodiment has been described with reference to an example in which the signal from the switch is input to the terminal NMI of the microcomputer, the signal is not limited to this, and the signal may be input to other input terminals.

Furthermore, although an example has been shown in which signals for opening and closing the switch are directly input from the switch, the present invention is not limited to this, and any means may be used as long as the microcomputer can determine whether the switch is open or closed. There is no problem. Furthermore, the position of the throttle lever can be arbitrarily selected other than the half-throttle position depending on the surrounding situation.

〔Effect of the invention〕

As described above, in the present invention, when the prime mover is stopped, the power supply to the drive control unit is not cut off at the same time (the drive control unit is used to position the hydraulic cylinder at a position where a predetermined amount of fuel can be supplied, Since the power to the drive control section is cut off after the operation is completed, the prime mover can be easily started even in cold weather.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an engine control device according to an embodiment of the present invention, FIG. 2 is a block diagram of a specific example of the control section shown in FIG. 1, and FIG. 3 is an operation of the device shown in FIGS. 1 and 2. FIG. 4 is a system diagram of a conventional engine control device. 1...Engine, 3...Hydraulic pump,
4...Private equipment, 5...Hydraulic cylinder,
7, 8... Solenoid valve. 9... Fuel solenoid valve, 10... Position detector, 12... Switch, 16... Control section, 17... Stable power supply Circuit, 18...
Electronic equipment, 19...Accumulator.

Claims (1)

[Claims] A prime mover, a hydraulic pump driven by the prime mover,
A control device for a prime mover including a hydraulic cylinder that is driven by the hydraulic pump and adjusts the amount of fuel supplied to the prime mover, and a drive control unit that controls the drive of the hydraulic cylinder in accordance with a command. an accumulator for accumulating the hydraulic cylinder, a positioning means for driving the hydraulic cylinder to a predetermined position by the accumulator in response to a stop operation of the prime mover, and a power source for cutting off the power to the drive control section when positioning is completed by the positioning means. 1. A control device for a prime mover, characterized in that it is provided with a shutoff means.