JPH0323329A - Fuel feed control device - Google Patents

Abstract

PURPOSE:To reliably prevent overrotation of an engine by a method wherein, in a device to increase an amount of fuel during a starting, the reference number of revolutions compared with a detecting result of a rotation detecting means is switched during the increase and the decrease of the number of revolutions according to the rotation state of an engine. CONSTITUTION:When an engine starting command is issued, a starter motor 29 is rotated by a controller 28, and a PID control part 2 starts control. In the PID control part 2, the number of idling revolutions is set as the target number of revolutions. But, since the number of revolutions of an engine is sufficiently lower than the target number of revolutions during the starting of an engine 22, a PWM signal is outputted in a duty ratio of 100% from a comparator CMP 2, an output therefrom is inputted to a CMP 1, and a linear solenoid 27 of an electronic governor 26 is prevented from drive. When the number of revolutions of an engine exceeds a value available during an increase and an output from the CMP 1 is increased to H, a drive signal is outputted to the linear solenoid 27 until the number of revolutions is reduced to a value lower than a value available during a decrease.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a fuel supply control device that supplies an amount of fuel according to a control state to an engine that is a prime mover that drives a generator or the like.

(bl Conventional Technology) In an engine used as a prime mover for a generator, etc., it is necessary to control the rotation speed according to the load condition of the main device such as the generator. For this reason, an electronic governor that supplies fuel to the engine The control rack included in this electronic governor is displaced to change the amount of fuel supplied to the engine.A linear solenoid is generally used to displace this control rack, and the voltage applied to this linear solenoid is changed. This causes the control rack to be displaced via the actuator. PWM control is used to change the voltage applied to this linear solenoid, and the linear solenoid is driven at a duty ratio depending on the amount of fuel supplied. Additionally, since starting an engine generally requires a larger amount of fuel than during normal operation, the linear solenoid is driven at 100% duty ratio after the starter motor is turned on until the engine speed reaches a certain speed. be done.

(C) Problems to be Solved by the Invention However, conventional fuel supply control devices include a rotation speed detection means for detecting the engine rotation speed, and after the starter motor is driven at the time of engine startup, the rotation speed detection means remains constant. A voltage was continuously applied to the linear solenoid at a duty ratio of 100% until the rotation speed was detected. For this reason, for example, if the rotation speed detection means has a failure such as a disconnection, the engine rotation speed cannot be used to control the fuel supply amount, and even after the engine has started, 100% of the linear solenoid There was a problem in which the voltage was continued to be applied at the DEAT ratio, and a large amount of fuel was continuously supplied to the engine from the electronic governor, causing the engine to overspeed. An object of the present invention is to supply fuel according to the engine rotation speed by switching the reference rotation speed for comparison with the detection result of the rotation detection means between when the rotation speed increases and when the rotation speed decreases according to the rotation state of the engine. The object of the present invention is to provide a fuel supply control device that can control the amount of fuel and reliably prevent engine overspeed. Means for Solving the FD1 Problem The fuel supply control device of the present invention includes a rotation speed detection means for detecting the rotation speed of the engine, and when the engine is started, the engine is operated until the detection result of the rotation speed detection means exceeds a predetermined rotation speed. A fuel supply control device that increases the amount of fuel supplied to a reference rotation speed switching means that sets the rotation speed at the time of increase to be less than the minimum rotation speed at the time of starting, and switches to the rotation speed at the time of descent, which is higher than the noise frequency of the power line when the detection result of the rotation speed detection means exceeds the rotation number at the time of increase; It is characterized by having the following.

(e) Effect In the present invention, the reference rotational speed in the comparison means is switched from the rising rotational speed to the descending rotational speed in accordance with the engine rotational speed. Therefore, when the rotation of the starter motor causes the detection result of the rotation speed detecting means to exceed the rising rotation speed when starting the engine, a fuel supply signal is output, and the amount of fuel supplied to the engine is increased. At this time, the reference rotational speed is switched to the descending rotational speed, and thereafter, fuel supply control is performed until the detection result of the rotational speed detection means becomes lower than the descending rotational speed. Since this rotational speed during descent is set to be higher than the noise frequency of the power supply line, the fuel supply will not be continued after the engine is stopped due to power supply noise.

(fl Embodiment FIG. 2 is a diagram showing the configuration of a power generator equipped with a fuel supply control device according to an embodiment of the present invention.

A rotating shaft of a generator 21 is fixed to a crankshaft 23 of an engine 22, and the generator 21 is driven by the rotation of the engine 22. An electromagnetic pin up 25 is attached to the flywheel 24 fixed to the crankshaft 23 of the engine 22.
are facing each other. This electromagnetic pink-up 25 detects a gear formed on the outer periphery of the flywheel 24 and inputs its detection pulse to the controller 28. The controller 28 includes a starter motor 29 provided in the engine 22.
is connected, and the engine 22 is started by rotation of the starter motor 29.

This engine 22 is supplied with fuel from an electronic governor 26 . The amount of fuel supplied from the electronic governor 26 increases or decreases depending on the displacement of the control rack 26a. This control rack 26a is displaced by the operation of the linear solenoid 27. The linear solenoid 27 is connected to a controller 28. The controller 28 counts the detection pulses input from the electromagnetic pickup 25 per unit time,
The rotation of the engine 22 is detected. The duty of the voltage applied to the linear solenoid 27 is controlled so that this detection result matches the target rotation speed determined by the load condition of the generator 21, etc., and the control lasso 26a is displaced by a predetermined amount. In particular, since a large amount of fuel is required when starting the engine 22, the linear solenoid 27 is driven at a 100% duty ratio. FIG. 1 is a circuit diagram showing the structure of the main parts of the fuel supply control device.

The rotational frequency of the engine 22 obtained by counting the detection pulses of the tm pickup per unit time is converted into a voltage signal by the F/V converter 1 and input to the non-inverting input terminal of the PID control section and comparator CMPI. The PID$IJ control unit 2 compares the rotation speed data output from the F/V converter 1 with target value data, and
The ID signal is input to the non-inverting input terminal of the comparator CMP2. A triangular wave generation circuit 3 is connected to the inverting input terminal of CMP2.
A triangular wave signal is input from the comparator CMP2, and a PWM signal is output from the comparator CMP2 with a duty ratio according to the PID signal.

The inverting input terminal of converter CMP 1 is supplied with the power supply voltage divided by resistors R+, Rz or resistors R,, R,, R, @ R,, R, or RI, Rs.
, Rt, which voltage dividing resistor is used to divide the voltage is determined by the on/off state of the transistor Q. That is, when transistor Q is off, the power supply voltage is
．． R. The voltage is divided by and input to the inverting input terminal of the comparator CMP1. When transistor Q is turned on, the power supply voltage is applied to resistors Rt, R:l . The voltage is divided by Rz. Since the base terminal of this transistor Q is connected to the output terminal of the comparator CMP 1, the transistor Q is turned on when the output of the comparator CMP 1 becomes "H t I1. Here, the resistors R,, R! The resistance values are set so that the power supply voltage divided by both is lower than the voltage corresponding to the minimum rotation speed at low temperature starting.In addition, the resistance values of the resistors R...R2, R! The power supply voltage divided by both is set to a value higher than the voltage corresponding to the noise frequency (60Hz) on the power supply line.With the above configuration, the engine 22 can be started by operating the starter inch, etc. When the command is given, controller 2
8 rotates the starter motor 29 and performs PID control related to driving the linear solenoid 27. At this time, the PID control unit 2 has the engine 22 as the target rotation speed.
The idling speed is set. On the other hand, engine 2
2 has not yet started, and the rotational speed of the engine 22 detected by the electromagnetic pickup 25 is sufficiently low relative to this target rotational speed. Therefore, the comparator CMP2 outputs a PWM signal with a duty ratio of 100%.

In this way, when the rotation speed of the engine 22 is sufficiently low, the rotation speed signal input to the non-inverting input terminal of the comparator CMPI is sufficiently small, and the rotation speed signal input to the non-inverting input terminal of the comparator CMPI is sufficiently low.
The output of is “Lo”. For this reason, the converter commercial
The drive signal output from P2 is input to the comparator CMP1 from the diode D, and no drive signal is input to the linear solenoid 27. When the tm pickup 25 is normal, the starter motor 29 drives the engine 22 and the crankshaft 23, and this rotation is detected by the electromagnetic pickup 25. When the rotation of the engine 22 starts at time t1 shown in FIG. When the rising rotational speed rb determined by the resistance value of
1, and a drive signal is input to the drive circuit 20 of the actuator 27. Also, converter commercial
When the output of PI becomes "Hi", the transistor Q is turned on, and the inverting input terminal of the comparator CMPI is connected to the resistor R+. A power supply voltage divided by R3 and Rz is input. As a result, after time t1 shown in FIG. 3, the resistances R, , R. , R2, the drive signal is inputted to the actuator 27 until the rotation speed ra during descent is lower than the rotation speed ra determined by the resistance values of R2. The duty ratio of this drive signal changes depending on the load condition of the generator 21 and the current rotation speed of the engine 22.

If the electromagnetic pink-up 25 has a failure such as a disconnection during start control of the engine 22, detection data comparable to the rotation speed exceeding the rising rotation speed rb is not input to the controller 28 even by the rotation of the starter motor 29. Therefore, the rotational speed voltage input to the non-inverting input terminal of the comparator CMP1 does not exceed the voltage at the inverting input terminal, and the output of the comparator CMP1 does not become "Hi". Therefore, the drive signal output from the comparator CMP2 continues to be input to the comparator CMPI via the diode D, and the linear solenoid 27 is not driven. In this way, electromagnetic pink Ambu 25
In the event of a failure, the fuel near solenoid 27 will not be driven, and fuel will not be supplied to the engine 22, thereby preventing the engine 22 from over-speeding.

As mentioned above, the rising rotational speed rb set by the resistance values of the resistors R, , R, is set lower than the minimum rotational speed at a low temperature start. Therefore, when the electromagnetic pickup 25 is in a normal state, the output of the comparator CMP 1 is always "Hi".
, the drive signal input to the comparator CMP2 is always input to the linear solenoid 27, and the engine 2
Fuel is reliably supplied to 2.

Note that if overspeeding occurs due to a sudden change in load or the like after the engine 22 is started, rotation prohibition control is generally performed to temporarily stop the rotation of the engine 22 in consideration of safety. After this rotation prohibition control is executed and the engine 22 is stopped, it is necessary to reset the overspeed detection signal so that the engine 22 can be reliably started the next time it is restarted. In the above embodiment, the rotational speed during descent, which is set by the resistance values of the resistors R+, Rs, and Rz, is set higher than 60 Hz, which is the noise frequency of the power supply line, so that the engine does not rotate due to noise from the power supply. There will be no false positives. Therefore, by resetting the overspeed detection signal when the rotation speed signal falls below the rotation speed ra during descent, the rotation prohibition WIS
H allows the overspeed detection signal to be reliably reset when the engine is stopped, and the engine 22 to be reliably started at the next restart. Also, depending on the external environment or fuel condition, the engine may stall after the cell mode is turned off. It is possible to reliably detect that the motor 22 has stopped, and immediately perform processing such as driving the starter motor again. (O Effect of the Invention According to this invention, since fuel supply is started when the detection result of the rotation speed detection means exceeds the rotation speed at the time of rising, it is possible to prevent the occurrence of overspeed due to a failure of the rotation detection means). can.
Furthermore, at this time, the reference rotational speed is switched to a descending rotational speed higher than the noise frequency of the power supply line, so there is an advantage that stopping of the engine after starting can be reliably detected.

This is a diagram showing changes in engine rotation speed. R, -R. 1-resistor (reference rotation speed switching means), Q-transistor (reference rotation speed switching means), 22-engine, 25-tfff pink up (rotation speed detection means).

Claims (1)

[Claims] (1) In a fuel supply control device that includes a rotation speed detection means for detecting the rotation speed of the engine, and increases the amount of fuel supplied to the engine until the detection result of the rotation speed detection means exceeds a predetermined rotation speed when the engine is started, comparing means for comparing the detection result of the number detecting means with a reference rotation speed and outputting a fuel supply signal; A fuel supply control device comprising: reference rotation speed switching means for switching to a fall rotation speed that is higher than the noise frequency of a power line when the detection result of the rotation speed detection means exceeds a rise rotation speed.