JP4618693B2 - Engine power generation system and controller thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine power generation system that rotates a generator with an engine and a controller thereof, and more particularly to an engine power generation system that starts an engine with a starter motor and a controller thereof.
[0002]
[Prior art]
In recent engine generators, in order to improve the power generation efficiency, the on-timing when power supply from the igniter to the primary side of the ignition coil is started, and the power supply from the igniter is cut off, and a high voltage is supplied to the secondary side of the ignition coil. Is controlled by a microcomputer (CPU).
[0003]
Here, the microcomputer detects that the engine rotation angle has reached a predetermined angle based on the output signal of the pulsar coil, calculates the on-timing and off-timing based on the engine speed and the like from this point, and further turns on The igniter is driven from timing to off timing to supply ignition energy to the primary side of the ignition coil.
[0004]
On the other hand, in an engine generator that starts an engine with a starter motor, when the starter motor is driven when the engine is started, power consumption increases momentarily due to the occurrence of an inrush current and the battery voltage temporarily decreases. For this reason, in a power generation system that supplies power to the microcomputer from a battery, the operation of the microcomputer may become unstable or the microcomputer may be reset when the engine is started.
[0005]
In order to solve such a problem, in the conventional engine generator, an exciter winding is provided in the generator separately from the main winding, and power is supplied to the microcomputer from the exciter winding.
[0006]
[Problems to be solved by the invention]
The driving time of the igniter also depends on the power supply voltage, and since the power supply voltage is low, if the driving time of the igniter, that is, the interval between the on timing and the off timing becomes long, the calculation time of the CPU becomes short. As a result, the CPU cannot accurately calculate the respective timings, making it difficult to improve the power generation efficiency.
[0007]
On the other hand, if power is supplied to the microcomputer from the exciter winding, the power supply voltage of the microcomputer does not decrease even when the engine is started by the starter motor. However, in order to generate the microcomputer operation guarantee voltage even at the cranking rotation speed at the start of the engine, the exciter winding must be enlarged, and an excessive voltage is generated at the time of high engine rotation.
[0008]
An object of the present invention is to solve the above-described problems of the prior art and provide a small-sized engine power generation system with high power generation efficiency and a controller thereof.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized in that the following measures are taken.
[0010]
(1) An engine power generation system of the present invention includes a generator driven by an engine, a starter motor that cranks the engine, and an electric power that includes the starter motor with a drive voltage that depends on the power supplied from the generator and the battery. And a controller for controlling the load, the controller including a voltage drop suppressing means for suppressing a drive voltage drop when the starter motor is driven.
[0011]
(2) The controller of the engine power generation system of the present invention supplies a drive voltage that depends on the power supplied from the engine generator and the battery to the starter motor of the engine, and a voltage drop that suppresses the drive voltage drop when the starter motor is driven. Including suppression means.
[0012]
According to each feature described above, even when the power consumption of the battery increases and the battery voltage decreases when the starter motor is driven, the drive voltage supplied to the electric load by the controller does not decrease. As a result, the voltage applied to the ignition coil by the controller can be kept high, and ignition energy can be supplied from the controller to the primary side of the ignition coil in a short time. Therefore, a sufficient time for the CPU of the controller to calculate the ignition timing and the like can be secured, and an engine power generation system with high power generation efficiency can be realized.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an engine power generation system according to an embodiment of the present invention, in which a generator 2 driven by the engine 1, a transformer 3 that steps down the output voltage of the generator 2, and output from the transformer 3. The controller 4 is supplied with the power generation voltage Vgene and the output voltage Vbatt of the battery 5, the ignition coil 6 and the ignition plug 7 driven by the controller 4, and the starter motor 8 for cranking the engine 1. .
[0014]
The controller 4 includes a rectifier circuit 41 that rectifies the generated voltage Vgene supplied from the transformer 3, an igniter 43 that supplies ignition energy to the temporary side of the ignition coil 6, its power supply 44, and a drive current to the starter motor 8. , A temperature sensor 48 for detecting the temperature of the engine 1, a pulsar coil 49 for detecting the rotation angle of the engine 1, and the igniter 43 and the driver 45 based on the engine temperature and the engine rotation angle. The CPU 46 and its power supply 47 and the limiting circuit 42 for limiting the output voltage and output current of the rectifier circuit 41 are the main components.
[0015]
FIG. 2 is a diagram showing the relationship between the drive voltage (point A voltage in FIG. 1) of the igniter 43 and the engine speed Ne in the present embodiment in comparison with the prior art, and FIG. 3 shows the present embodiment. It is the figure which showed the ON time of the igniter 43 in compared with a prior art.
[0016]
In the engine power generation system of FIG. 1, the engine 1 is cranked by the starter motor 8 at the start, but as shown in FIG. 2, the cranking rotational speed Nc by the starter motor 8 is higher than the engine rotational speed after complete explosion. Low. Therefore, conventionally, the generator 2 is equipped with a relatively large exciter coil so that the generator 2 can generate the required ignition voltage Vmin even at the cranking speed Nc. Therefore, when the engine reaches a high rotation state, an excessive voltage is generated.
[0017]
On the other hand, since the generator 2 of the present embodiment is equipped with an exciter coil that is smaller than the conventional one, no excessive voltage is generated even when the engine reaches a high rotation state. In Nc, the generated voltage Vgene is lower than the required ignition voltage Vmin.
[0018]
However, in the present embodiment, the battery power supply line is connected in parallel with the generator power supply line via the rectifier circuit 41, so that the power supply voltage of the igniter power supply 44 (point A in FIG. 1) The higher voltage of Vgene and battery voltage Vbatt is supplied. Accordingly, when the generated voltage Vgene falls below the battery voltage Vbatt during cranking, the battery voltage Vbatt is applied to the power line of the igniter power supply 44 via the diode D2. Therefore, a voltage equal to or higher than the battery voltage Vbatt is always applied to the power line of the igniter power supply 44.
[0019]
On the other hand, when the engine is started and the engine speed Ne increases, the output voltage Vgene of the rectifier circuit 41 increases in response. When the output voltage Vgene of the rectifier circuit 41 exceeds the battery voltage Vbatt, the power generation voltage gene is now applied to the power line of the igniter power supply 44 via the diode D1. Therefore, since the power line voltage of the igniter power supply 44 increases as the engine speed increases, the ON time of the igniter 43 can be shortened as the engine speed increases.
[0020]
Thus, according to the present embodiment, the battery voltage batt is supplied to the power line of the igniter power supply 44 during the cranking period when the engine speed is low, and the generated voltage Vgene is supplied after the engine is started. A predetermined drive voltage can be supplied to the igniter power supply 44 regardless of the engine speed without increasing the size of the coil. Therefore, as shown in FIG. 3, the ignition coil on-time can be shortened even during the cranking period when the engine speed is low, and the CPU 46 can secure a sufficient time for calculating the ignition timing and the like. Power generation efficiency is improved.
[0021]
Next, a drive control method for the starter motor 8 in the present embodiment will be described. In the present embodiment, starter control for reducing the power consumption of the starter motor 8 is performed at the initial stage of cranking.
[0022]
The driver 45 of the controller 4 includes a power FET 45a, and the CPU 46 performs PWM control on the gate voltage of the power FET 45a to variably control the power consumption of the starter motor 8. That is, as shown in FIG. 4, the CPU 46 increases the duty ratio of the pulse signal applied to the gate of the power FET 45a from 40% to 100% for a predetermined period (in this embodiment, 1 second) after the start of cranking. Increase gradually.
[0023]
FIGS. 5 and 6 are graphs showing a change in the starter current Im due to the starter control and a change in the power supply line voltage (point B in FIG. 1) of the CPU 46 in comparison with the prior art.
[0024]
According to the present embodiment, since the duty ratio of the pulse signal applied to the gate of the power FET 45a becomes small at the initial stage of cranking, the peak of the starter current Im can be kept low as shown in FIG. Therefore, as shown in FIG. 6, the driving voltage of the CPU 46 at the initial stage of cranking can be held higher than the reset voltage.
[0025]
Next, the burnout prevention system for the starter motor 8 according to the present embodiment will be described. The source / drain voltage VSD of the power FET 45a of the driver 45 and the starter current Im have a unique relationship as shown in FIG. 7, and the source / drain voltage VSD can represent the starter current Im.
[0026]
Therefore, in the present embodiment, the source / drain voltage VSD of the power FET 45a is constantly monitored by the CPU 46, and when the voltage VSD reaches the equivalent of an overcurrent, the power FET 45a is shut off and the drive of the starter motor 8 is stopped.
[0027]
【The invention's effect】
(1) According to the present invention, even if the power consumption of the battery increases when the starter motor is driven, the drive voltage supplied from the igniter of the controller to the primary side of the ignition coil does not decrease. The igniter on-time can be shortened even during the cranking period. Therefore, a sufficient time for the CPU to calculate the ignition timing and the like can be ensured, and this can be calculated accurately, so that an engine power generation system with high power generation efficiency and its controller can be provided.
[0028]
(2) According to the present invention, during the cranking period, the drive current of the starter motor is reduced to reduce the power consumption of the battery and the power supply voltage in the controller is suppressed, so the drive voltage of the CPU built in the controller is reduced. It can always be held above the reset voltage.
[Brief description of the drawings]
FIG. 1 is a block diagram of an engine power generation system according to an embodiment of the present invention.
FIG. 2 is a diagram showing the relationship between the engine speed and the power supply voltage of the igniter according to the present invention in comparison with the prior art.
FIG. 3 is a graph showing the relationship between the engine speed and the igniter on time according to the present invention in comparison with the prior art.
FIG. 4 is a diagram for explaining starter control according to the present invention.
FIG. 5 is a diagram comparing the change over time of the starter current according to the present invention with that of the prior art.
FIG. 6 is a graph showing the relationship between the engine speed and the power supply voltage of a CPU according to the present invention in comparison with the prior art.
FIG. 7 is a diagram showing a relationship between a source / drain voltage VSD of a power FET that switches a starter current Im and a starter current Im.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Generator, 3 ... Transformer, 4 ... Controller, 5 ... Battery, 6 ... Ignition coil, 7 ... Ignition plug, 8 ... Starter motor, 48 ... Temperature sensor, 49 ... Pulser coil

Claims (4)

A generator driven by an engine;
A starter motor for cranking the engine;
A controller for controlling an electric load including the starter motor with a drive voltage depending on the electric power supplied from the generator and the battery,
The generator includes an exciter coil that cannot output the required ignition voltage at the cranking speed of the engine,
The controller is
An igniter for supplying ignition energy to an engine ignition coil;
Supplying a drive voltage, which is obtained by connecting a power supply line of the exciter coil and a power supply line of the battery in parallel, consisting of a higher voltage between the power generation voltage of the exciter coil and the voltage of the battery, to the power line of the igniter And an engine power generation system.   2. The engine power generation system according to claim 1, wherein the controller includes a voltage drop suppression unit that suppresses a drive voltage drop when the starter motor is driven.   The engine power generation system according to claim 2, wherein the voltage drop suppression unit variably controls a duty ratio of a drive voltage supplied to the starter motor.   4. The engine according to claim 3, wherein the voltage drop suppression unit sets a duty ratio of a drive voltage supplied to the starter motor to be small when the starter motor is started, and then gradually increases as time elapses. Power generation system.

Images