JPH0469020A - Alternator controller - Google Patents

Abstract

PURPOSE:To improve fuel consumption performance and to prevent overcharge of battery by calculating the difference between the battery terminal voltage and the alternator generating voltage and setting the target generating voltage at high voltage side if thus calculated difference exceeds a predetermined value in negative direction. CONSTITUTION:A control unit 20 judges whether an engine 1 is starting based on a starter signal (a) and upon judgment of starting, a low target voltage VL is set as a target generating voltage V0. Upon judgment of not starting, an electric load 4 is judged whether it is turned ON and when the electric load 4 is turned ON, a judgment is made whether engine temperature Tw represented by a water temperature signal (e) is higher than a reference water temperature T0. Furthermore, judgments are made whether or not, the engine is accelerating and whether it is operating under heavy load or not. Upon judgment of acceleration or heavy load operation, the low target voltage VL, is set as the target generating voltage V0.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an alternator driven by an engine,
In particular, the present invention relates to an alternator control device that can adjust the generated voltage.

(Prior Art) Generally, a vehicle engine is equipped with a generator that constitutes a charging system, but this type of generator usually uses an alternator, and this alternator is driven by the engine. The alternating current generated by this is converted into direct current by a rectifier, and the direct current is used for charging storage batteries and the like. In this case, the alternator converts the kinetic energy generated by the engine into electrical energy, so operating the alternator consumes extra fuel and reduces the net drive torque. Become. Therefore, in some types of engines, a variable alternator control system that controls the alternator generated voltage under predetermined conditions is sometimes adopted for the purpose of improving fuel efficiency, driving performance, and the like. For example, Japanese Patent Application Laid-Open No. 59-22099 discloses that the total load current supplied to the electrical load is detected, and the alternator IT pressure is switched between a high power generation state and a low power generation state in accordance with the detected total load current. The configuration of such a variable alternator control system is shown. According to this, since the alternator is switched to a low power generation state when current consumption is low, the drive torque of the alternator is reduced, and improvement in fuel efficiency is expected.

(Problems to be Solved by the Invention) However, in the conventional variable alternator control system, the following problems may occur.

That is, when alternator control is performed, the amount of power generated by the alternator decreases in a low power generation state, and accordingly, the charging current distributed to the storage battery also decreases. Therefore, if alternator control is performed when the storage battery is in a discharge state, the alternator will not generate enough power in a low power generation state.
Due to the lack of flow, it takes time for the storage battery to reach a fully charged state, and during this time the alternator is driven more often under high load conditions, making it impossible to expect a significant improvement in fuel efficiency. .

Moreover, there is a risk that excessive discharge will occur in the storage battery due to insufficient charging current, which will also cause new problems in terms of durability.

The present invention addresses the above-mentioned actual situation in alternators where variable alternator control is performed, and aims to realize an alternator control device that can further improve fuel efficiency and prevent excessive discharge of storage batteries.

(Means for Solving the Problem) That is, an alternator control device according to the invention of claim 1 of the present application (hereinafter referred to as the first invention) is an alternator that is driven by an engine and whose generated voltage is adjustable. a first voltage detection means for detecting the generated voltage of the alternator; a second voltage detection means for detecting the terminal voltage of the storage battery connected to the alternator; The present invention is characterized by comprising a control means that calculates a deviation from the alternator generated voltage and sets the target generated voltage of the alternator to the high voltage side when the deviation is greater than or equal to a predetermined value in the negative direction.

In addition, the invention of claim 2 of the present application (hereinafter referred to as the second invention)
The alternator control device according to the above is an alternator that is driven by an engine and whose generated voltage can be adjusted,
A first voltage detection means for detecting the generated voltage of the alternator, a second voltage detection means for detecting the terminal voltage of a storage battery connected to the alternator, and a storage battery terminal detected by the first and second voltage detection means. The present invention is characterized by comprising a control means that calculates a deviation of the voltage from the alternator generated voltage, and sets the target generated voltage of the alternator to increase in accordance with the deviation as the deviation becomes larger in the negative direction.

(Function) According to the alternator control device according to the first invention, when the deviation of the storage battery terminal voltage from the alternator generated voltage shows a value greater than or equal to a predetermined value in the negative direction, the target generated voltage of the alternator is set to the high voltage side. As a result, the storage battery quickly becomes fully charged, reducing the rate at which the alternator is driven under high load, and reducing the average alternator drive torque, resulting in lower fuel consumption compared to conventional alternator control. Performance is further improved, and an over-discharge state of the storage battery due to insufficient charging current is avoided.

Further, according to the alternator control device according to the second invention,
The larger the deviation of the storage battery terminal voltage from the alternator generated voltage in the negative direction, the larger the target generated voltage of the alternator is set according to the deviation. The state of full charge is reached more quickly, and the average driving torque of the alternator is also further reduced.
Even better fuel efficiency can be obtained. Also in this case, an over-discharge state of the storage battery due to insufficient charging current can be avoided.

(Example) Examples of the present invention will be described below.

First, FIG. 1 shows the first embodiment and the second embodiment according to the first invention.
To explain the general configuration of the electrical system of the engine 1 that is common to the second embodiment of the invention, the engine 1 is equipped with a starter 2 for starting the engine, and is equipped with a storage battery 3 whose one terminal side is grounded to the body. One end of a starting line 6 branched from a power supply line 5 connected to the terminal and supplying power to an ignition system and electrical loads 4 such as various meters, lamps, actuators, etc. is connected to a power receiving terminal of the starter 2. A starter switch 7, one end of which is grounded to the body, is connected to one terminal of the starter 2. Therefore, when the starter switch 7 is closed, a closed circuit is formed between the storage battery 3 and the starter 2, whereby a starting current is supplied to the starter 2, and a rotational driving force is generated in the starter 2. . This rotational driving force is then transmitted to the crankshaft 9 of the engine body 8, and the engine 1 starts to start.

On the other hand, the engine 1 is equipped with an alternator 10 that is body grounded, and this alternator 10 is equipped with a well-known regulator 1 that adjusts the alternator generated voltage 4.
1 is provided. This regulator 11 is provided with a B terminal 12 for taking out the alternator generated voltage VA to the outside, and a power supply line 13 is interposed between this B terminal 12 and the power supply line 5.

Here, to explain the outline of the self-voltage regulation action by the regulator 11, when the alternator generated voltage vA is lower than the regulation voltage, the regulator 11 controls the field coil (not shown) for field generation provided in the alternator 10. Turn on electricity. As a result, the magnetic field generated by the field coil increases, and the alternator generated voltage (4) output to the B terminal 12 also increases accordingly. On the other hand, when the alternator generated voltage VA becomes higher than the above-mentioned regulated voltage, the regulator 11 cuts off the power supply to the above-mentioned field coil. Therefore, the magnetic field of the field coil disappears, and the output of the alternator generated voltage vA is stopped. By repeating such control in a short period of time, the alternator generated voltage vA is maintained near the regulated voltage.

The regulator 11 is equipped with a G terminal 14 for controlling the regulated voltage from the outside, and the amount of current flowing through the field coil changes depending on the voltage applied to the G terminal 14, causing the alternator to generate a voltage ■A is variably controlled. In this case, the G terminal 14
As the applied voltage is lowered, the current flowing through the field coil tends to decrease, and the alternator generated voltage (A) also decreases accordingly.

Further, the alternator 10 is provided with an input shaft 15, and a driven pulley 16 provided on the input shaft 15, a drive pulley 17 provided on the crankshaft 9 of the engine main body 8, and A power transmission belt 19 is wound around the idler 18 which is rotatably supported. Therefore, when the engine 1 is operating, the rotational force of the engine 1 output to the crankshaft 9 is transmitted to the input shaft 15 of the alternator IO via the belt 19, and the rotational force causes the alternator 1
0 is driven to generate power. When the alternator 10 is driven, the alternator current output from the B terminal 12 of the regulator 11 is transmitted to the power supply line 5 via the power supply line 13 and supplied to the electric load 4, and is also used to charge the storage battery 3. It is also being used as an electric current.

The engine 1 is equipped with a control unit 20 that adjusts the voltage generated by the alternator 10. This control unit 20 includes the starter 2
and the alternator current signal from the current sensor 21 installed on the power supply line 13 leading from the alternator 10 to the power supply line 5, the alternator generated voltage signal C also taken out from the power supply line 13.
, a storage battery terminal voltage signal d extracted from a power supply line 5 close to the storage battery 3, an engine water temperature signal e from a water temperature sensor 22 that detects the engine water temperature, and a storage battery terminal voltage signal d taken out from the power supply line 5 close to the storage battery 3; The engine rotation speed signal f from the crank angle sensor 23 and the throttle opening signal g from the throttle opening sensor 24 representing the engine load are input. Then, the target power generation voltage V is determined according to these signals a to g. At the same time as setting this target power generation voltage V. alternator 10 so that
An alternator control signal i is output to the G terminal 14 of the regulator 11 at .

In the first embodiment, the target power generation voltage V is set in advance in the control unit 20. as high voltage target value V
H (e.g. 14.4V) and low voltage target value VL (e.g. 1
2.8V) is set, and when the deviation of the storage battery terminal voltage VB from the alternator generated voltage ■A shows a value greater than a predetermined value α (for example, 0.I V ) in the negative direction, the target The high voltage target value VH is selected as the generated voltage vo.

Next, the operation of the above embodiment will be explained using the alternator control flowchart shown in FIG.

That is, the control unit 20 inputs various signals in step S1, and first determines whether or not the engine 1 is being started based on the starter signal a in step S2. If it is determined that the startup is in progress, step S1□ is executed to set the target power generation voltage V. and set the low voltage target value VL. As a result, the drive torque consumed by the alternator 10 is reduced, making it possible to obtain good starting performance.

On the other hand, when the control unit 20 determines in step S2 that the startup is not in progress, step S
3, it is determined whether the electric load 4 is in the ON state. When the electric load 4 is ON-[Q, the process advances to step S4, and the engine water temperature Tw indicated by the water temperature signal e is the reference water temperature T. (
For example, if the engine water temperature Tw is higher than the reference water temperature To, the alternator current IA indicated by the alternator current signal is determined in step S5.
It is determined whether or not is smaller than a reference current IO (for example, 10A). Then, the electric load 4 is in the ON state, and the engine water temperature TW is the reference water temperature T.

and when it is determined that the alternator current IA is lower than the reference current IO, the storage battery terminal voltage signal d
The alternator generated voltage signal C indicates the storage battery terminal voltage VB indicated by the alternator generation voltage signal C! Deviation from voltage VA △
V (△V-V, -VB) is calculated, and it is determined whether the deviation △V is smaller than a predetermined value α (step S6,
S7).

When the deviation △■ is smaller than the predetermined value α, the control unit 20 determines whether acceleration is in progress based on the rate of change in throttle opening calculated from the throttle opening indicated by the throttle opening signal g in step S8. If the engine 1 is not accelerating, it is determined in step S9 whether the engine 1 is operating under high load based on the throttle opening. If it is determined that the acceleration or high load operation is in progress, the process moves to step Sl+ and the target power generation voltage ■ is set. and set the low voltage target value VL. As a result, the alternator 10 is operated at a low load, reducing engine output loss and improving driving performance.

On the other hand, for example, after starting, a large amount of the electric charge stored in the storage battery 3 is consumed and the storage battery terminal voltage VB decreases significantly, and as shown in FIG.
1, when the deviation ΔV exceeds the predetermined value α, the control unit 20 executes step Slo in the flowchart to set the target power generation voltage V. Set the high voltage target value ■H as As a result, the alternator generated voltage VA rapidly increases to match the high voltage target value vH as shown by arrow A in FIG. 3, and the storage battery 3 is charged by the accompanying increase in the alternator current I^. Particularly, the storage battery terminal voltage VB shown by the broken line also rises rapidly as shown by arrow A in the figure, approaching the alternator generated voltage VA. In this case, as the amount of electricity stored in the storage battery 3 increases, the storage battery terminal voltage VB
The rate of increase in the storage battery terminal voltage VB decreases, and the storage battery terminal voltage VB hardly changes in the fully charged state.

Then, at time t2 when the storage battery 3 is fully charged and the deviation V reaches a predetermined value α, for example, when the vehicle is accelerating, the control unit 20 executes step Sll of the flowchart to achieve the target value. Power generation voltage V
The low voltage target value VL is set as o. This results in
The alternator generated voltage VA also decreases, and as shown by the arrow in FIG. 3, it is MIl to match the low voltage target value ■L. In other words, in the conventional alternator control, the increase in the storage battery terminal voltage VB was slow and the time t3 at which the battery reached a fully charged state was delayed, as shown by the chain line in FIG. 3, but this has been greatly improved. The rate at which the alternator 10 is operated at a low load increases by the time difference Δt (Δ=−t3 t2), resulting in a significant improvement in fuel efficiency.

Furthermore, when the alternator generated voltage vA is controlled to match the low voltage target value VH, such as during high load operation, the storage battery terminal voltage VB is lower than the alternator generated voltage ■A as shown in FIG. , the control unit 20 skips steps S7 to S8.89 of the above flowchart, executes step SIO, and sets the high voltage target value ■H as the target power generation voltage ■o. . As a result, as shown by the arrow in FIG. 4, the alternator generated voltage VA rapidly rises to the high voltage target value VH, and the charging current for the storage battery 3 increases due to the alternator current that increases accordingly. As a result, the storage battery terminal voltage VB shows an increasing tendency as shown by the broken line. This prevents the storage battery 3 from being over-discharged due to insufficient charging. In addition, this high voltage state is caused by the deviation △ of the storage battery terminal voltage ■8 with respect to the alternator generated voltage VA.
It is canceled when V reaches the predetermined value α, and the alternator generated voltage VA is returned to the previous low voltage state.

In addition, since the storage battery 3 is returned to a fully charged state quickly when it is in a discharged state, the rate at which the alternator 10 is operated under high load is reduced on average.
Adopting alternator control will significantly improve fuel efficiency.

Next, referring to FIGS. 5 to 7, the second invention corresponding to the second invention will be explained.
An example will be explained.

That is, in this second embodiment, the alternator 1
As shown in FIG. 5, the target power generation voltage VO of 0 is set to change in multiple stages according to the deviation ΔV of the storage battery terminal voltage VB with respect to the alternator power generation voltage VA.

That is, the control unit 20 sets the target power generation voltage V when the deviation ΔV is smaller than, for example, the reference deviation value α0 (for example, 0. I V ). and select a low voltage target value vL (for example, 12.8V), and if V exceeds the standard deviation value α0 and the first deviation value α1 (for example, 0°5
V) until reaching the reference high voltage target value■□. (For example, 1
4.4V), and the deviation △V is the first deviation value between this first deviation value α and the second deviation value α2 (for example, IV).
The high voltage target value Vow (for example, 14.7V) and the second
Between the deviation value α2 and the 31st difference value α3 (for example, 1.5 V), the second high voltage target value VH2 (for example, 15.
OV), and when the deviation △V exceeds the third deviation value α3, the third high voltage target value VM3 (for example, 1
6.0V).

The control unit 20 sets the target power generation voltage V in advance as shown in FIG. The duty ratio of the alternator control signal i corresponding to the selected target power generation voltage Vo is determined with reference to the duty ratio map set as a parameter. In this case, as the duty ratio increases, the proportion of the G terminal 14 of the regulator 11 in FIG. 1 being grounded increases. therefore,
The smaller the target power generation voltage Vo, the lower the duty rate becomes 10.
As the voltage approaches 0%, the current flowing through the field coil decreases, and the alternator generated voltage (4) output to the B terminal 12 also decreases.

According to the configuration of the second embodiment, the deviation ΔV of the storage battery terminal voltage VB with respect to the alternator generated voltage VA is
As shown in FIG. 7, when the third deviation value α3 is larger than the third deviation value α3, the third high voltage target value VH3 is selected as the target power generation voltage Vo.

Therefore, since the alternator generated voltage ■^ is controlled to be higher than the reference high voltage target value vHo, the storage battery 3
The ratio of the charging current distributed to the storage battery 3 increases and rapid charging is performed, which causes the storage battery terminal voltage VB to rise quickly, and the storage battery 3 is fully charged in a shorter time than in the first embodiment. state. In addition, control unit 2
0, as the deviation △V decreases, the target power generation voltage ■o is sequentially switched to a lower target value, and finally when the deviation △V reaches the reference deviation value α0, the alternator power generation voltage ■
A is controlled so that it matches the normal reference high voltage target value VHI). Dear, at that point, for example, engine 1
When operating under high load, the target power generation voltage V. is changed to the low voltage target value V, and as a result, the alternator generated voltage V^ is controlled to match the low voltage target value VL as shown by the arrow O in FIG.

(Effects of the Invention) As described above, according to the alternator control device according to the first invention, when the deviation of the storage battery terminal voltage from the alternator generated voltage shows a value greater than or equal to a predetermined value in the negative direction, the target generated voltage of the alternator is Since it is set on the high voltage side,
The storage battery quickly becomes fully charged, reducing the rate at which the alternator is driven under high load, reducing the average driving torque of the alternator, resulting in improved fuel efficiency compared to conventional alternator control. At the same time, an over-discharge state of the storage battery due to insufficient charging current can be avoided.

Further, according to the alternator control device according to the second invention,
The larger the deviation of the storage battery terminal voltage from the alternator generated voltage in the negative direction, the larger the target generated voltage of the alternator is set according to the deviation. The state of full charge is reached more quickly, and the average driving torque of the alternator is also further reduced.
Even better fuel efficiency can be obtained.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is an electrical system diagram of the engine common to the first and second embodiments, a flow chart of alternator control in the first embodiment, and FIG.
FIG. 4 is a time chart diagram showing the operation of the first embodiment, FIG. 5 is a control characteristic diagram showing the relationship between the deviation of the storage battery terminal voltage with respect to the alternator generated voltage and the target generated voltage in the second embodiment, and FIG. Similarly, the figure is a characteristic diagram showing the duty ratio of the alternator control output with respect to the target generated voltage, and FIG. 7 is a time chart diagram showing the operation of the second embodiment. 1... Engine, 3... Storage battery, 10... Alternator, 20... Control unit (first voltage detection means, second voltage detection means, control means).

Claims (2)

[Claims] (1) In an alternator that is driven by an engine and whose generated voltage is adjustable, a first voltage detection means detects the generated voltage of the alternator, and a second voltage detection means detects the terminal voltage of a storage battery connected to the alternator. and calculating the deviation of the storage battery terminal voltage detected by the first and second voltage detection means with respect to the alternator generated voltage, and when the deviation is greater than or equal to a predetermined value in the negative direction, the target of the alternator is determined. 1. An alternator control device comprising: control means for setting a generated voltage to a high voltage side. (2) In an alternator that is driven by an engine and whose generated voltage is adjustable, a first voltage detection means detects the generated voltage of the alternator, and a second voltage detection means detects the terminal voltage of a storage battery connected to the alternator. and the deviation of the storage battery terminal voltage detected by these first and second voltage detection means from the alternator generated voltage is calculated, and the larger the deviation is in the negative direction, the higher the target generated voltage of the alternator is determined according to the deviation. 1. A control device for controlling an alternator, comprising: control means for setting a value such that the value increases.