JPH104698A - Power generation controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent stalling of an internal combustion engine, a decrease in the durability of a rotation transmission mechanism and heat damage, which increasing the output current, without addition of a dedicated mechanism. SOLUTION: A power generation controller for internal combustion engine is provided with an alternator 11, a rotational speed sensor 35 and a controller 28. The rotational speed sensor 35 detects the rotational speed of a rotor, which is a state quantity associated with the torque and the temperature of the alternator 11. The controller 28 detects the voltage of a battery 31, connected with the alternator 11, to control the energizing for field coil 16, according to the value detected. The controller 28 limits the energizing amount for the field coil 16, in order to decrease the maximum torque (upper limit of the duty ratio is decreased from 100% to 70%), when the rotational speed of the alternator 11 reaches the condition equivalent to the torque being predetermined threshold or higher (when it belongs to low rotational speed of about 1,500rpm).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation control device for controlling energization of a field coil in a generator driven and connected to an internal combustion engine.

[0002]

2. Description of the Related Art In a general vehicle, a charging device including an alternator and a regulator is used for charging a battery, supplying power to an electric device, and the like. The alternator includes a rotor having a field coil, and a stator coil disposed around the rotor. The rotor is drivingly connected to a crankshaft of the internal combustion engine via a rotation transmission mechanism such as a pulley or a belt, and is rotated at an increased speed with the operation of the internal combustion engine. When the field coil is energized during this rotation, an alternating current is generated in the stator coil. The AC output is converted (rectified) into a DC output by a diode. The regulator controls the energization of the field coil in accordance with the voltage of the battery.

In the charging device having the above-described configuration, as shown in FIG. 9, generally, when a maximum amount of current flows through a field coil, the output current tends to increase as the rotation speed of the alternator increases. . On the other hand, the torque of the alternator tends to be maximum in a low rotation speed range of about 1500 rpm.

During operation of the alternator, a load having a magnitude represented by the product of the torque and the rotation speed is applied to the internal combustion engine. Therefore, the pulley ratio (the ratio between the diameter of the pulley on the crankshaft side and the diameter of the pulley on the alternator side)
The larger is set, the higher the speed of rotation of the alternator rotor and the greater the output current, but the greater the load applied to the internal combustion engine. This increase in load causes a stall of the internal combustion engine. Further, when the load increases, the belt and the pulley slip, and there is a problem that the durability of the belt decreases.

Further, the temperature of the alternator is 2000
It tends to be maximum in a low rotation speed range of about rpm. If overheated due to the rise in temperature, the components of the alternator may be deteriorated or burnt out.

As a technique for dealing with such a problem,
For example, there is a "variable speed accessory drive control device for an internal combustion engine" disclosed in Japanese Utility Model Laid-Open Publication No. 63-160465. In this apparatus, a continuously variable belt transmission 54 is interposed between a crankshaft 52 of an internal combustion engine 51 and an alternator 53 as shown in FIG. This mechanism 54
The movable portion 56 of the pulley 55 is moved in the axial direction (the left-right direction in FIG.
The distance between the pulley 55 and the fixed portion 58 is adjusted, the effective diameter of the pulley 55 is continuously changed, and the substantial pulley ratio is changed.

In the above device, the controller 59 reads the actual rotation speed of the alternator 53 by the rotation speed sensor 60, and the actual rotation speed is set to the target rotation speed (for example, 2
000 rpm). Then, the movable portion 56 is moved in the axial direction, the effective diameter of the pulley 55 changes, and the pulley ratio is adjusted. In addition, the controller 59 includes a temperature sensor 61
The temperature of the alternator 53 is read, and when the temperature becomes larger than a predetermined value with an increase in load,
Set the target rotation speed to a value other than 2000 rpm (for example, 300 rpm).
0 rpm). The drive of the actuator 57 is controlled so that the actual rotation speed converges on the changed target rotation speed. With this control, the alternator 53 is driven in a rotational speed range where the torque does not become maximum at the time of high load,
The belt 62 is less likely to slip. Also, the cooling fan 63
This increases the air volume and prevents the temperature of each part of the alternator 53 from rising excessively.

[0008]

However, according to the apparatus disclosed in the above-mentioned publication, the belt 62 can be prevented from slipping to prevent a decrease in durability and prevent heat damage to the alternator 53, but the pulley ratio is changed. Therefore, since the continuously variable transmission belt transmission mechanism 54 is added, there is a problem that the size and complexity of the entire apparatus cannot be avoided.

The present invention has been made in view of the above-described circumstances, and has as its object to increase the output current, stall the internal combustion engine without adding a special mechanism, reduce the durability of the rotation transmission mechanism, It is to eliminate the occurrence of heat damage.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a generator having a rotor which is drivingly connected to an internal combustion engine by a rotation transmitting mechanism, and which generates electricity by energizing a field coil of the rotor. Power generation of an internal combustion engine, comprising: voltage detection means for detecting the voltage of a secondary battery connected to the generator; and power supply control means for controlling power supply to the field coil in accordance with the voltage from the voltage detection means. In the control device, a state quantity detecting means for detecting at least one of a torque, a temperature of the generator and a state quantity related thereto, and at least one of the torque and the temperature by the state quantity detecting means has become a predetermined value or more. Or when the state quantity reaches a state corresponding thereto, the field coil is controlled by the energization control means so as to reduce the maximum value of the torque or the temperature. It is provided with energization amount limiting means for limiting the amount of energization.

According to the present invention, when the rotor is rotating with the operation of the internal combustion engine, the power supply control means controls the power supply to the field coil in accordance with the voltage of the secondary battery by the voltage detection means. The generator generates electricity by energizing the coil. The energization amount limiting unit is configured to switch to a state when at least one of the torque and the temperature of the generator detected by the state amount detection unit is equal to or more than a predetermined value,
When the state quantity detected by the state quantity detection means is reached, the amount of current supplied to the field coil by the current supply control means is limited.

This limit lowers the maximum value of the generator torque. Therefore, at the time of power generation, a load having a magnitude represented by the product of the torque of the generator and the rotation speed is applied to the internal combustion engine. However, as described above, the load becomes small due to a decrease in the maximum value of the torque, and Institutions are less likely to stall. Also, no excessive force is applied to the rotation transmission mechanism that transmits the rotation of the internal combustion engine to the generator, and the durability of the mechanism is improved. Further, the maximum value of the temperature of the generator is reduced due to the limitation of the amount of electricity, so that heat damage to the generator is less likely to occur.

In addition, since the maximum value of the torque of the generator is reduced, if the load of the internal combustion engine is kept constant, the rotation speed of the generator can be increased accordingly. In other words, the rotation amplification ratio by the rotation transmission mechanism (for example, pulley ratio)
Is set to a large value, and the generator can be rotated at high speed. In a general generator, the output current tends to increase as the rotation speed increases,
By setting a large rotation amplification ratio, it is possible to increase the output current in the low rotation speed region of the internal combustion engine.

Further, in the present invention, it is possible to prevent the stall of the internal combustion engine, the decrease in the durability of the rotation transmitting mechanism, and the heat damage by only limiting the amount of current to the field coil. There is no need to add a special mechanism or device.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The vehicle is equipped with a charging device including an alternator (alternating current generator) and an IC regulator. FIG. 3 shows the internal structure of the alternator 11. The alternator 11 includes a rotor 12, a stator 13, and a rectifier 14.

The rotor 12 is a part functioning as a field, and includes a pole core (magnetic pole) 15, a field coil 16,
It is constituted by a shaft 17 and the like. Shaft 17
Is rotatably supported by a case 19 by a pair of bearings 18, 18 (front and rear in FIG. 3). A pulley 21 is attached to the front end of the shaft 17 exposed from the case 19. The pulley 21 and a crank pulley (not shown) attached to a crankshaft of the internal combustion engine have a belt 22 having a corrugated cross-sectional shape. Is wrapped around. The diameter of the pulley 21 is about 1 of the diameter of the crank pulley.
/ 2, so that the rotor 12 is rotated at approximately twice the speed of the crankshaft. The pulley 21, the belt 22, and the crank pulley constitute a rotation transmission mechanism.

In the rotor 12, when a current flows through the field coil 16, one of the pole cores 15 becomes an N pole and the other pole core 15 becomes an S pole. A slip ring (not shown) is mounted on the rotor 12, from which an exciting current is supplied to the rotating rotor 12. A cooling fan 23,
A fan 23 is attached, and air is introduced into the case 19 by the fans 23 to cool the rotor 12 and the like.

The stator 13 includes a stator core 24 disposed around the rotor 12 and three sets of stator coils 25 wound around the core 24. The stator core 24 is a magnetic flux path formed so that the magnetic flux emitted from the pole core 15 intersects the stator coil 25, and is composed of a plurality of thin iron plates superimposed on each other. The stator 13 generates a three-phase alternating current with the rotation of the rotor 12. The rectifier 14 incorporates a rectifier circuit and rectifies the three-phase alternating current generated in the stator coil 25 into direct current.

The IC regulator 26 controls the energization of the field coil 16. next,
The electrical configuration of the charging device will be described. As shown in FIG. 2, the IC regulator 26 includes a controller 28 having a memory 27 and a transistor 29. The base of the transistor 29 is connected to the controller 28, and the emitter is grounded. Transistor 29
Is connected via a terminal 30 and a field coil 16 to a positive terminal of a battery 31 as a secondary battery. On the other hand, a positive terminal of the battery 31 is connected to the controller 28 via a terminal 32 and an ignition switch 33, and a rotation speed sensor 35 is connected via a terminal 34. The sensor 35 is attached to the alternator 11 and detects the number of rotations of the shaft 17 per unit time, that is, the rotation speed N of the alternator 11. The controller 28 reads the battery voltage VB and the rotation speed N from the rotation speed sensor 35, and turns on / off the transistor 29 based on these values VB and N, thereby controlling the duty of the current to the field coil 16.

In the duty control, the energization time is controlled by the duty ratio Fduty, and the average current is variably controlled in an analog manner by digitally changing the ratio of energization and non-energization. Duty ratio Fdu
ty indicates the ratio of the energization time to the time of one cycle. Therefore, as shown in FIG. 5, when the time of one cycle is C and the energization time during the time C is Ca, the duty ratio Fduty (%) is expressed by (Ca / C) · 100.

In FIG. 2, reference numeral 25 denotes three sets of Y-connected stator coils, and reference numeral 36 denotes a rectifier having six diodes for full-wave rectification of the three-phase alternating current generated in the stator coil 25. Circuit.

When the field coil 16 is energized with a duty ratio of 100%, that is, when a maximum amount of current flows, the charging device exhibits characteristics as shown by broken lines in FIGS. 4 and 8. The output current of the alternator 11 increases as the rotation speed N increases. The torque of the alternator 11 becomes maximum in a low rotation speed range of about 1500 rpm. The temperature of the alternator 11 is 2000 rpm
It becomes maximum in the low rotation speed range. This temperature characteristic is due to the fact that the field coil 16 and the like generate heat when energized. Here, although the components inside the alternator 11 are cooled to some extent by the rotation of the cooling fan 23, the amount of ventilation of the fan 23 changes according to the rotation speed N. Therefore, the temperature of the alternator 11 exhibits a characteristic depending on the rotation speed N as described above.

Next, the operation and effect of the embodiment constructed as described above will be described. The flowchart of FIG. 1 shows a routine executed by the controller 28 to control the energization of the field coil 16 and is executed at a predetermined timing.

First, at step 105, the controller 28 reads the battery voltage VB and the rotation speed N from the rotation speed sensor 35. Step 11
At 0, it is determined whether or not the battery voltage VB is higher than a determination value a. The determination value a is for determining whether or not the alternator 11 needs to charge the battery 31. If the determination condition of the step 110 is satisfied (VB> a), it is determined that the charging of the battery 31 is not necessary.
9 is turned off, and this routine ends. Accordingly, at this time, the field coil 16 is not energized, and the alternator 11 does not generate power.

If the determination condition in step 110 is not satisfied (VB ≦ a), in step 120, the map in the memory 27 is searched to calculate the upper limit b of the duty ratio Fduty corresponding to the rotation speed N. I do. As shown in FIG. 6, in this map, the rotation speed N is 1000 r
The upper limit b is set to 100% in an area lower than pm and an area higher than 2000 rpm. The duty ratio Fduty of 100% means that the current continues to flow through the field coil 16. The rotation speed N is 1000
In an area of not less than 2000 rpm and not more than 2000 rpm, the upper limit value b is smaller than 100% (for example, 70 to 80).
%). This area includes the alternator 11
Is the rotation speed range when the torque of the rotation speed becomes substantially maximum.

Next, in step 125 of FIG. 1, it is determined whether or not the transistor 29 is turned on. If this determination condition is satisfied (transistor 29: on), the on-time (elapsed time after switching from off to on, described as “continuous on-time” in FIG. 1) is set to the upper limit in step 130. It is determined whether or not it is equal to or more than the product of b and time c. This product is the upper limit of the energizing time required to reduce the maximum value of the torque of the alternator 11. If this determination condition is satisfied, it is determined that the field coil 16 has been energized for the energizing time, the transistor 29 is turned off in step 135, and this routine ends. Step 1
If the determination condition of 30 is not satisfied, it is determined that the energization needs to be continued, and the transistor 29 is turned on in step 140, and this routine ends.

On the other hand, if the determination condition of step 125 is not satisfied (transistor 29: off), the off time (elapsed time after switching from on to off, in FIG. 1, "continuous off time" in step 145) Is determined to be greater than the product of (1-b) and time c. This product is the non-energizing time required to reduce the maximum value of the alternator 11. If this determination condition is satisfied, it is determined that the energization of the field coil 16 has been stopped for the non-energization time, and the transistor 29 is turned on in step 150, thus ending this routine. On the other hand, if the determination condition in step 145 is not satisfied, it is determined that the energization needs to be further stopped, and the transistor 29 is turned off in step 155, thus ending this routine.

In the above routine, the controller 2
The process of step 105 (more specifically, the process of reading the battery voltage VB) by step 8 corresponds to the voltage detecting means.
Steps 110, 115, 135, 140, and 15
Each of the processes 0 and 155 corresponds to an energization control unit. The processing in step 120 corresponds to the power supply amount limiting unit.

As described above, in the present embodiment, attention is paid to the fact that the torque of the alternator 11 is maximized in the low rotation speed range, and when the alternator 11 is rotating in this range, the upper limit value b of the duty ratio Fduty is set. Limited (reduced). Due to this restriction, the maximum value of the torque of the alternator 11 decreases as shown by the solid line in FIG. Therefore, during power generation, a load having a magnitude represented by the product of the torque and the rotation speed N is applied to the internal combustion engine. However, as described above, the load is reduced due to a decrease in the maximum value of the torque, and the internal combustion engine is stalled. It becomes difficult to do. Further, no excessive force is applied to the rotation transmitting mechanism (particularly, the belt 22) for transmitting the rotation of the internal combustion engine to the alternator 11, and the durability of the mechanism is improved.

In addition, since the maximum value of the torque of the alternator 11 becomes small, if the load of the internal combustion engine is fixed,
Accordingly, the rotation speed N of the alternator 11 can be increased. In other words, the rotation amplification ratio by the rotation transmission mechanism (in this case, the pulley ratio) is set to a large value,
The rotor 12 of the alternator 11 can be rotated at high speed. In the general alternator 11, as described above, the output current tends to increase as the rotation speed N increases. Therefore, by setting the large rotation amplification ratio as described above, the low rotation speed region of the internal combustion engine is set. , The output current can be increased.

Also, only by limiting the amount of current (duty ratio Fduty) to the field coil 16,
Since it is possible to prevent the stall of the internal combustion engine, the decrease in the durability of the rotation transmission mechanism, and the heat damage, it is not necessary to add a special mechanism or device for the prevention.

Although not shown, the amount of heat generated by the field coil 16 and the like decreases due to the limitation of the duty ratio Fduty, and the maximum value of the temperature of the alternator 11 decreases. This is because the rotation speed range where the torque of the alternator 11 is maximum and the rotation speed range where the temperature is maximum overlap. For this reason, the occurrence of heat damage due to the temperature rise can be prevented. As the heat damage, for example, a welded portion of the field coil 16 may be blown, or parts near the weld may be deteriorated by heat.

Although the output current of the alternator 11 may slightly decrease as shown by the solid line in FIG. 4, the adverse effect is negligibly small. This embodiment has the following features in addition to the items described above.

(A) In the prior art, since the movable portion 56 of the pulley 55 is moved in the axial direction to be separated from the fixed portion 58, the usable belt is limited to the V-belt.
With this V-belt, there is a limit in setting a large pulley ratio, and it is difficult to secure a large output current in a low rotation speed region of the internal combustion engine. On the other hand, in the present embodiment, it is only necessary to limit the upper limit value b of the duty ratio Fduty, and a belt 22 having a corrugated cross-sectional shape can be used. Therefore, the pulley ratio can be set larger than that of the above-described V-belt, and a large output current can be obtained even in a low rotation speed region of the internal combustion engine.

The present invention can be embodied in another embodiment shown below. (1) In the above-described embodiment, utilizing the fact that there is a correlation between the torque of the alternator 11 and the rotation speed N (the torque becomes maximum in a low rotation speed region), the rotation speed N is related to the torque. The rotation state sensor 35 detects the amount of state to be performed. Instead, the torque and the temperature of the alternator 11 may be directly detected by a sensor. In this case, a predetermined value is set in advance in consideration of the stall of the internal combustion engine, the slip of the belt, the occurrence of heat damage, and the like, and when the actual torque or temperature detected by the sensor is equal to or more than the predetermined value. The amount of current (duty ratio) to the field coil 16 is limited.

For example, according to the temperature, the duty ratio Fduty
When the upper limit b is limited, a map as shown in FIG. 7 is created in advance. In this map, the temperature is a predetermined value d.
In the following cases, the upper limit b of the duty ratio Fduty is 100
% Is set. When the temperature becomes higher than the predetermined value d, the upper limit b is set to be smaller in inverse proportion to the temperature rise. The upper limit value b is determined using this map, and the duty ratio Fdu is set so as not to exceed the upper limit value b.
If the energization control of the field coil 16 is performed at ty, the maximum value of the temperature of the alternator 11 becomes low, and heat damage hardly occurs.

(2) In connection with the above (1), the duty ratio Fduty may be limited based on the combination of the rotation speed N, the torque and the temperature of the alternator 11 as appropriate.

(3) In the above embodiment, the alternator 1
Although the first rotation speed N is detected by the rotation speed sensor 35, the rotation speed of the internal combustion engine may be multiplied by the pulley ratio, and the result of the multiplication may be used as the rotation speed N. For controlling the injection amount and the ignition timing of the internal combustion engine, the engine speed detected by a speed sensor is usually used. Therefore, if the detected value of the rotation speed sensor is used as the rotation speed of the internal combustion engine when calculating the rotation speed N, the rotation speed sensor 35 can be omitted.

Although the embodiments of the present invention have been described above, technical ideas other than the claims that can be grasped from each embodiment will be described below together with their effects. (A) In the control device according to claim 1, the state quantity detected by the state quantity detecting means is a rotation speed of the generator, and the predetermined value by the power supply amount limiting means is substantially equal to the torque or temperature of the generator. The power generation control device of the internal combustion engine, which is the rotation speed of the generator at the maximum.

In a generator, there is generally a correlation between torque or temperature and rotation speed. For this reason, even if the torque or the temperature is not directly detected, the maximum value of the torque or the temperature can be reduced by restricting the amount of energization based on the comparison result between the rotation speed and the predetermined value.

(B) In the control device according to the first aspect, the state quantity detected by the state quantity detecting means is a torque or a temperature of a generator, and the predetermined value by the current quantity limiting means is a maximum value of the current quantity. A power generation control device for an internal combustion engine having a value lower than the maximum value of the torque or temperature of the engine.

By doing so, the maximum value of the torque or the temperature can be reduced by limiting the amount of current supply based on the result of the comparison between the torque or the temperature and the predetermined value, and the effect of the present invention can be reliably achieved. be able to.

[0043]

According to the present invention, since the maximum value of the torque of the generator can be reduced by limiting the amount of current supplied to the field coil, the rotation speed increase ratio such as the pulley ratio by the rotation transmission mechanism is set large. However, the output current can be increased. In addition, the stall of the internal combustion engine, the decrease in the durability of the rotation transmission mechanism, and the occurrence of heat damage can be eliminated without adding a dedicated mechanism.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a process executed by a controller to control energization of a field coil.

FIG. 2 is an electric circuit diagram showing an electric configuration of the charging device.

FIG. 3 is a sectional view showing the internal structure of the alternator.

FIG. 4 is a characteristic diagram showing a relationship between a duty ratio, a torque, and an output current with respect to a rotation speed of an alternator.

FIG. 5 is a timing chart for explaining a duty ratio.

FIG. 6 is a diagram showing a map defining an upper limit value of a duty ratio with respect to a rotation speed of an alternator.

FIG. 7 is a diagram showing a map defining an upper limit of a duty ratio with respect to an alternator temperature in another embodiment.

FIG. 8 is a characteristic diagram showing a relationship between the rotation speed of the alternator and the temperature.

FIG. 9 is a characteristic diagram showing output characteristics of a conventional alternator.

FIG. 10 is a schematic configuration diagram showing a conventional charging device.

[Explanation of symbols]

11 ... alternator as a generator, 12 ... rotor, 1
Reference numeral 6: field coil, 21: pulley constituting a part of the rotation transmitting mechanism, 22: belt constituting a part of the rotation transmitting mechanism, 28: controller functioning as voltage detecting means, energizing control means and energizing amount limiting means, 31: a battery as a secondary battery; 35: a rotational speed sensor as a state quantity detecting means; VB: a battery voltage.

Claims (1)

[Claims] 1. A generator that has a rotor that is drivingly connected to an internal combustion engine by a rotation transmission mechanism and that generates power by energizing a field coil of the rotor, and detects a voltage of a secondary battery connected to the generator. A power generation control device for an internal combustion engine, comprising: a voltage detection unit that controls the power supply to the field coil in accordance with the voltage detected by the voltage detection unit. A state quantity detecting means for detecting at least one of the state quantities to be performed, and when at least one of the torque and the temperature by the state quantity detecting means is equal to or more than a predetermined value, or when the state quantity is in a state corresponding thereto. And a power supply limiting means for limiting the power supply to the field coil by the power supply control means in order to reduce the maximum value of the torque or the temperature. Power generation control system of the engine.