JP2009148090A - Power generation control apparatus for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power generation control apparatus for vehicle, having a capacitor and a battery to improve fuel efficiency, while improving the power generation efficiency of an alternator and remarkably improving effects of fuel efficiency. <P>SOLUTION: A battery 4 is charged based on the power generation output of the alternator 2 and a capacitor 5 is also charged at a constant voltage (threshold voltage of a high voltage side), and then, a field current is turned off to stop the alternator 2 (so-called alternator-cut state), and the energy stored in the capacitor 5 is supplied to the load. Accordingly, a field current is prevented from continuously flowing to the alternator 2, and further, the alternator 2 can be controlled only by the power generation output at a threshold voltage or higher of high voltage side, and power generation efficiency is improved. Thus, the fuel efficiency is improved by providing the capacitor 5 and the battery 4, the power generation efficiency of the alternator 2 can be improved and the effects of fuel efficiency can be remarkably improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular power generation control device configured to charge a capacitor with a power generation output of an alternator and effectively use the energy of the alternator after battery charging to improve fuel efficiency, and more particularly to improvement of power generation efficiency of the alternator. .

  Generally, a vehicle power generation control device mounted on a vehicle (automobile) is basically configured by combining an alternator, a starter (cell motor), and a battery (mainly lead storage battery).

  When the starter is driven by the energy of the battery and the engine is started, the rectified power generation output of the alternator is mainly used for charging the battery and driving a load (general load) in the vehicle.

  At this time, the alternator switches the output voltage between high and low by automatic adjustment based on battery voltage monitoring in order to prevent wasteful power generation and improve fuel efficiency. For example, in the case of a vehicle alternator equipped with a rated 12V battery It is suggested that the high voltage VH of 14.5V when charging the battery, and the low voltage (battery open voltage) VL of 12.8V while the battery is kept fully charged by floating charge after charging. (For example, refer to Patent Document 1). This is because the battery has higher impedance as the charging progresses, and it becomes difficult for the charging current to flow. Therefore, after the battery is fully charged, there is no problem even if the voltage of the power generation output of the alternator is switched to the low voltage VL.

  Incidentally, in recent years, it has also been proposed to further improve the fuel consumption by further including a capacitor in the vehicle power generation control device and charging the capacitor with the power generation output of the alternator.

JP 2004-72874 A (abstract, claim 1, paragraphs [0010], [0022], FIG. 1, etc.)

  In this type of vehicle power generation control device, when engine brake deceleration occurs after battery charging, fuel cut is performed during this deceleration, and even if the power generation output of the alternator is high voltage VH, the fuel consumption does not decrease. If the battery or capacitor is charged with the high voltage VH, the engine output (regenerative energy) during deceleration can be used effectively. Therefore, during the deceleration, the output voltage of the alternator is switched from the low voltage VL to the high voltage VH.

  However, in the configuration in which only the battery is charged with the power generation output of the alternator, the voltage of the power generation output of the alternator is switched from the low voltage VL to the high voltage VH during the deceleration period T as shown in FIG. In the fully charged battery, almost no charging current flows as shown in FIG. For this reason, the power generation output of the alternator cannot be used effectively, and the fuel efficiency improvement effect is small.

  On the other hand, in the case of a configuration including a capacitor together with a battery, if the voltage of the power generation output of the alternator is switched from the low voltage VL to the high voltage VH during the deceleration period T as shown in FIG. Since energy can be stored according to the voltage as long as there is no limit, the charging current flows and energy is stored as shown in FIG. 5B, so that the power generation output of the alternator can be used effectively and fuel efficiency is improved. When the deceleration is completed, the output voltage of the alternator returns to the low voltage VL, and the stored energy of the high voltage VH of the capacitor is preferentially supplied to the general load.

  Therefore, in the case of a configuration including a battery and a capacitor, it is effective in terms of fuel efficiency improvement to switch the voltage of the power generation output of the alternator from the low voltage VL to the high voltage VH during deceleration.

  By the way, even if a capacitor is provided together with the battery and the voltage of the power generation output of the alternator is switched from the low voltage VL to the high voltage VH during deceleration, a sufficient fuel efficiency improvement effect cannot be obtained if the power generation efficiency of the alternator is low. In particular, when the running condition is steady running without acceleration / deceleration, the alternator's power generation voltage is not switched, so that a sufficient fuel efficiency improvement effect cannot be obtained.

  Moreover, since the alternator maintains the output voltage at least at the low voltage VL, as is well known, excitation (field) current (hereinafter referred to as field current) always flows, and electric loss torque is generated. .

  Moreover, the power generation efficiency inherent to the alternator generally shows the characteristics shown in FIG. 7 with respect to the rotational speed of the engine. Usually, since the electric load is less used during running, the alternator is used within a range of electric efficiency of about 10A. The

  As described above, the power generation efficiency of the alternator can be improved by providing the capacitor together with the battery and switching the voltage of the power generation output of the alternator from the low voltage VL to the high voltage VH while decelerating to effectively use the power generation output. It is not possible to achieve a dramatic improvement in fuel efficiency.

  An object of the present invention is to improve a fuel consumption by providing a capacitor together with a battery, improve the power generation efficiency of an alternator, and dramatically improve the fuel efficiency improvement effect.

  In order to achieve the above object, a vehicle power generation control device of the present invention is a vehicle power generation control device including a battery and an alternator, and is provided in a state of being connected in parallel to the battery. A capacitor for storing energy charged by the power generation output, a battery charge detection means for detecting the charge state of the battery, a capacitor voltage detection means for detecting the voltage of the capacitor, and the battery charge detection means is charged by a predetermined amount or more. When the amount is detected and the detection voltage of the capacitor voltage detection means becomes equal to or higher than the threshold on the high voltage side, the field current of the alternator is turned off, the generator is stopped, and the stored energy of the capacitor is reduced. And a control means for controlling power supply to the load (Claim 1).

  Further, in addition to the control means, when the detection voltage of the capacitor voltage detection means falls below a threshold on the low voltage side during the control of the power generation stop state of the alternator, the field current is turned on to stop the power generation. It is characterized by comprising means for canceling the state control and controlling the power feeding by the power generation output of the alternator and the charging of the capacitor (claim 2).

  Further, the charge amount equal to or greater than the predetermined value is a charge amount in a fully charged state (claim 3).

  In the vehicle power generation control device according to the first aspect of the present invention, when the battery is charged and the capacitor is also charged to a voltage equal to or higher than a certain voltage (high voltage side threshold voltage), the alternator automatically generates a field current. The power generation is stopped (so-called alter cut state), and the energy stored in the capacitor is supplied to the load. As a result, the field current does not always flow in the alternator, and the alternator is controlled only to the power generation output equal to or higher than the threshold voltage on the high voltage side, thereby improving the power generation efficiency. A capacitor is provided with the battery, and even if the power generation output voltage of the alternator is switched from a low voltage to a high voltage during deceleration or the like, the charging current to the capacitor is added to the power generation output of the alternator to increase the power generation efficiency of the alternator. Although the power generation efficiency is improved, the power generation efficiency of the alternator is further increased and the power generation efficiency is further improved in the present invention by making the power generation output of the alternator in place of the alternator cut instead of lowering the voltage.

  Therefore, it is possible to improve the fuel consumption by providing the capacitor together with the battery, and it is possible to improve the power generation efficiency of the alternator, and to dramatically improve the fuel efficiency improvement effect.

  Moreover, even when the alternator is cut off, the power supply for load power such as auxiliary equipment is duplicated between the battery and the capacitor, so even if the terminal connection of the battery is loose or disconnected, for example, Power supply backup is performed, and loads on vehicles such as auxiliary machinery do not inadvertently enter a power outage (power supply stop) state, and the reliability of the charging system of the vehicle including the alternator may be reduced by the alternator cut. Absent.

  In the case of the vehicle power generation control device according to the second aspect of the present invention, when the alternator is in the alternator cut state and the accumulated energy of the capacitor is supplied to the load, and the voltage of the capacitor drops below the threshold on the low voltage side, In the alternator, the field current is turned on to release the alternator cut, and the power is returned to the power generation output state to charge the load and charge the capacitor. When the battery is charged and the capacitor is also charged to a certain voltage (high voltage side threshold voltage) or more, the alternator is again in the alternator cut state, and the accumulated energy of the capacitor is supplied to the load. By repeating the same operation, the alternator can be used in the efficiency improvement region even during steady running.

  In this case, the alternator is intermittently driven in the state of the power generation output of the threshold voltage on the high voltage side with high power generation efficiency, and is in the alternator cut state during the rest period. Therefore, the power generation efficiency of the alternator can be further improved, and the fuel efficiency improvement effect can be further improved dramatically.

  In the case of the vehicle power generation control device according to the third aspect of the present invention, the alternator is in the alternator cut state with the battery fully charged, and the effects of the first and second aspects of the invention can be achieved with extremely practical control. Play.

  Next, in order to describe the present invention in more detail, an embodiment thereof will be described in detail with reference to FIGS.

  FIG. 1 is a connection diagram of the vehicle power generation control device of the present embodiment mounted on the vehicle 1, FIG. 2 is a flowchart for explaining the operation of FIG. 1, and FIG. 3 performs alternating by monitoring only the state of charge of the battery. It is a flowchart for operation | movement description in a case.

(Constitution)
In FIG. 1, reference numeral 2 denotes an alternator, an output terminal 2p is connected to a power supply line 3 of a load (auxiliaries, etc.), a field current terminal 2f is connected to a control ECU 6 described later, and a ground terminal 2n is an engine block. While the vehicle body frame is grounded and the field current is being fed, the alternating current generated according to the rotation of the engine of the vehicle 1 is rectified to form a power generation output.

  Reference numeral 4 denotes a battery having a rating of 12 V, for example, the positive terminal 4p is connected to the power supply line 3, and the negative terminal 4n is grounded to the vehicle body frame.

  Reference numeral 5 denotes a large-capacity energy storage capacitor that is charged by the power generation output of the alternator 2, and includes an electric double layer capacitor, a hybrid capacitor, and the like. One end 5p is connected to the feeder 3 and the other end 5n is connected to the vehicle body frame. Grounded.

  Reference numeral 6 denotes a control ECU having a microcomputer configuration for controlling the alternator 2, and more specifically, an ECU for electronic control of fuel injection.

  Reference numeral 7 denotes a current sensor for detecting a charging / discharging current of the battery 3, and outputs a battery current detection signal S1 to the control ECU 6 to form the battery charge detection means of the present invention together with the control ECU 6. Reference numeral 8 denotes a voltage sensor for detecting the voltage of the capacitor 5, which forms the capacitor voltage detection means of the present invention, and outputs a capacitor voltage detection signal S2 to the control ECU 6.

  9 is a warning lamp section of the vehicle 1, and when a charge lamp output for notifying the charging system abnormality of the control ECU 6 is input, the charging lamp is turned on (or flashes) and the charging system abnormality including the abnormality of the alternator 2 is detected. Is notified. In FIG. 1, the starter and the like are omitted.

  The control ECU 6 supplies the field current power to the terminal 2f of the alternator 2 while the ignition is on, and simultaneously outputs the control signal S3 of the power generation operation to the alternator 2, for example, by PWM controlling the field current, thereby controlling the alternator 2. The power generation output of the high voltage VH or the OV (field current off) alter cut is controlled. Further, in order to monitor the control state, the detection signal S4 of the duty of the field current is taken. Further, the charge ramp signal S5 generated by the alternator 2 when the alternator is cut is also taken in.

  Further, the control ECU 6 has the following first to fourth functions and various functions of electronic control of fuel injection by software processing.

<First function>
This function detects the state of charge (charge amount) of the battery 4 every moment based on the battery current detection signal S1.

<Second function>
This function forms the control means of claim 1, detects that the battery 4 has a charge amount greater than or equal to a predetermined value, and sets the detection voltage of the capacitor 5 based on the capacitor voltage detection signal S2 to a high level. When the voltage exceeds the threshold on the voltage side, the field current of the alternator 2 is turned off, the alternator 2 is placed in the alternator cut (power generation stop) state, and control is performed to load-feed the accumulated energy of the capacitor 5.

<Third function>
This function forms the means of claim 2, and while the alternator 2 is controlled to be in the alternator cut state, the detection voltage of the capacitor voltage detection signal S <b> 2 falls below the threshold value on the low voltage side, whereby the alternator The field current of No. 2 is turned on to cancel the alternator control, and control is performed for load feeding by the power generation output of the alternator 2 and charging of the capacitor 5.

<Fourth function>
This function is a function of prohibiting the output of the charge lamp to the warning lamp unit 9 with respect to the input of the charge lamp signal S5 while the alternator 2 is controlled to the alternator cut by the second function. This function prevents erroneous lighting of the charge lamp of the warning lamp unit 9 by alternator control.

  The amount of charge of the battery 4 that is greater than or equal to a predetermined value in the second function may be appropriately determined based on the charge / discharge characteristics, capacity, and the like of the battery 4, but the battery 4 is normally maintained in a fully charged state. Therefore, in this embodiment, the most practical full charge amount is set. Further, the threshold value on the high voltage side and the threshold value on the low voltage side of the capacitor 5 are improved in terms of fuel consumption in a state where the battery 4 is not discharged as much as possible in consideration of the voltage of the battery 4 having a predetermined charge amount or more, the withstand voltage of the capacitor 5 and the like. In this embodiment, the threshold on the high voltage side of the capacitor 5 is set to the high voltage VH (14.5 V) of the alternator 2, and the threshold on the low voltage side of the capacitor 5 is set to the low voltage of the alternator 2 in this embodiment. Set to VL (12.8V).

  The control ECU 6 also receives various signals of the running state of the vehicle 1 such as the vehicle speed, the accelerator opening, and the brake lamp signal.

(Operation)
Based on the above configuration, the vehicular power generation control device of FIG. 1 generally operates as shown in steps A1 to A13 of FIG.

  That is, after the engine is started, the control ECU 6 turns on the field current at step A1 in FIG. 2 to set the alternator 2 to the power generation output of the high voltage VH. Based on this power generation output, the battery 4 is fully charged by step A2. Charge. At this time, the capacitor 5 is also charged.

  Then, when it is detected by the first function of the control ECU 6 that the battery 4 is fully charged, the process proceeds from step A2 in FIG. 2 to steps A3 and A4 to step A5, and from the capacitor voltage detection signal S2. It is determined whether or not the capacitor 5 is equal to or higher than the threshold voltage VH on the high voltage side.

  At this time, if the capacitor 5 is charged to the high voltage side threshold voltage VH or higher by the power generation output of the alternator 2, the process proceeds from step A5 to step A6 in FIG. The field current of the alternator 2 is turned off to place the alternator 2 in an alternator cut (power generation stop) state, and the stored energy of the high voltage VH of the capacitor 5 is load-fed.

  And it transfers to step A7 from step A6 of FIG. 2, and it is judged whether it is accelerating from accelerator opening etc. FIG. At this time, if the vehicle is accelerating, the process returns from step A7 to step A3 via steps A8 and A9. If not accelerating, the process proceeds from step A7 to step A10, and it is determined whether or not the vehicle is decelerating. If the vehicle is decelerating, the process returns from step A10 to step A3 via steps A11 and A9. If not, the process returns from step A10 to step A3 via step A9.

  At this time, since the alter cut is being executed, the process proceeds from step A3 to step A12 via step A4, and the capacitor 5 is discharged so that the voltage falls below the threshold voltage VL on the low voltage side. Until that time, step A12 is passed in the affirmative (YES), loop control returning from step A7 to step A3 via step A8, A9 or step A10, A9 is executed, and the alternator cut state is maintained.

  Then, when the voltage of the capacitor 5 becomes lower than the threshold voltage VL on the low voltage side, step A12 in FIG. 2 is negated (NO) and the process proceeds to step A13, and the third function of the control ECU 6 Then, the field current is turned on to release the alternator cut, the alternator 2 is returned to the state of the power generation output of the high voltage VH, and the capacitor 5 is charged. At this time, if the battery 4 is in a discharged state of, for example, several Ah (a state in which the amount of charge is large) in order to compensate for the power generation shortage of the alternator 2, step A9 in FIG. 2 is passed in affirmative and step A1 is performed through step A1. The process shifts to A2, and priority is given to the charge monitoring of the battery 4 by the power generation output of the high voltage VH of the alternator 2.

  On the other hand, if the battery 4 is in a very small discharge state (a state in which the amount of charge is low) of, for example, several hundred milliAh or less, step A9 of FIG. This step A3 is passed in the affirmative and the process proceeds to step A13. The alternator 2 is maintained at the power generation output of the high voltage VH, and the battery 4 and the capacitor 5 are charged with the power generation output of the high voltage VH.

  Then, when the battery 4 is fully charged and the capacitor 5 is also charged to the high voltage VH so that the load power supply is covered by the power generation output of the alternator 2, step A3 in FIG. The process proceeds to step A6 via A5, and the second function of the control ECU 6 again controls the alternator 2 to the alternator cut to control the load feeding of the stored energy of the capacitor 5.

  If the engine is braked during the alternator cut and the engine is decelerated, the engine rotates in the fuel cut state. Therefore, the process proceeds from step A10 to step A11 in FIG. The current is turned on to release the alternator cut, and the alternator 2 is brought into a power generation output state of the high voltage VH to charge the capacitor 5 with regenerative energy.

  Therefore, in the case of this embodiment, the battery 4 and the large-capacity capacitor 5 can be provided to improve fuel efficiency. Further, the alternator 5 is controlled to either the drive in the power generation state of the high voltage VH with high power generation efficiency or the alternator cut without wasting energy by turning off the field current, and the alternator 5 is controlled to the high voltage VH with high power generation efficiency. Therefore, the power generation efficiency of the alternator 5 can be improved, and the fuel efficiency improvement effect can be greatly improved.

  Moreover, even when the alternator 2 is in the alternator cut state, the battery 4 and the capacitor 5 are duplicated in the power supply for load power supply such as auxiliary equipment, so the terminal connection of the battery 4 is loose for some reason. Even if the power supply is disconnected, the power supply is backed up by the capacitor 5 so that the load on the vehicle such as auxiliary equipment is not inadvertently brought into a power failure (power supply stop) state, and the charging system of the vehicle 1 including the alternator 2 The reliability is not reduced by the alternator cut.

  In addition, when the alternator 2 is in the alternator cut state, the fourth function of the control ECU 6 can prohibit the output of the charge lamp from the control ECU 6 to the warning lamp unit 9, and the charging of the warning lamp unit 9 can be prohibited. There is an advantage that the lamp is prevented from being erroneously turned on and the reliability and the like are improved.

  By the way, in the case of improving fuel efficiency by simpler control than the above control, it can be considered that the control ECU 6 performs control as shown in the flowchart of FIG.

  3, steps A1 to A3, A7 to A11, and A13 correspond to the same steps in FIG. 2, and the difference is that the processing of steps A4 to A6 and A12 in FIG. Step B is provided in the middle of the path from the negative side of Step A3 to Step A7 in order to control the alternator 2 in an alternator cut.

  When the control of FIG. 3 is performed, if the battery 4 is fully charged by the power generation output of the high voltage VH of the alternator 2, it is considered that the capacitor 5 is also charged to the high voltage VH at this time, and step A2 From step A3 to step B, and the alternator 5 is set to the alternator cut state in which the field current is turned off.

  Further, when a decrease in the charge amount of the battery 4 is detected in the alternator cut state, the alternator is canceled and the alternator 2 is switched to a high voltage by transition from step A3 to step A13 or from step A9 to step A1. Control to VH power generation output.

  When configured in this manner, the charging state of the battery 5 is monitored, and the alternator 2 is driven either in the power generation state of the high voltage VH with high power generation efficiency, or in the alternator cut with no wasteful energy consumption with the field current turned off. Thus, the alternator 2 can be intermittently driven in the power generation state of the high voltage VH with high power generation efficiency, and the power generation efficiency of the alternator 2 can be improved, and the fuel efficiency improvement effect can be improved even during steady running.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, the threshold voltages on the high voltage side and the low voltage side are not limited to the high voltage VH and the low voltage VL of the alternator 2.

  In addition, the present invention can be applied in the same manner even when the configuration and capacity of the battery 4 and the capacitor 5, the fully charged voltage of the battery 4, the high voltage VH and the low voltage VL of the alternator 2 are different from the embodiment. it can. For example, the present invention can be applied to the case where the positive terminal 4p of the battery 4 is grounded to the vehicle body frame, the negative terminal 4n is connected to the feeder 3, and the polarity of the terminal connection of the battery 4 is opposite to that of the above embodiment. The same can be applied.

  Furthermore, the control procedure of the control ECU 6 is not limited to that shown in FIG. Then, for example, in step A3 of FIGS. 2 and 3, it is determined whether or not the battery 4 is in a discharged state from the current direction of the battery 4. If the battery 4 is in a discharged state, step A3 is passed in an affirmative and the alternator 2 is switched to a high voltage. You may make it make it the electric power generation output of VH. Moreover, you may provide the control means of this invention other than control ECU6.

  Next, the present invention can be similarly applied to the case where the alternator 2 has the general configuration shown in FIG. In FIG. 4, the control signal S3 is a PWM control signal, and controls the alternator 2 to a high voltage VH power generation output, a low voltage VL power generation output, or an intermediate power generation output therebetween. S6 is a power supply line to the regulator in the alternator 2, and the power supply of the alternator 2 is stopped by setting the power supply line S6 to 0V.

  The present invention can be applied to a vehicle power generation control device mounted on various vehicles.

It is a connection diagram of one embodiment of the present invention. It is a flowchart for operation | movement description of FIG. It is a flowchart for operation | movement description in the case of performing an alternator cut by monitoring only the charge condition of a battery. It is explanatory drawing of the other example of the alternator of FIG. The relationship between the voltage of the alternator during deceleration and the charging current of the battery when only the battery is mounted is shown, (a) is a voltage waveform diagram of the alternator, and (b) is a waveform diagram of the charging current of the battery. The relationship between the voltage of the alternator during deceleration and the charging current of the capacitor when a battery and a capacitor are mounted is shown, (a) is a voltage waveform diagram of the alternator, and (b) is a waveform diagram of the charging current of the capacitor. It is a characteristic view of an example of the power generation efficiency of an alternator.

Explanation of symbols

1 Vehicle 2 Alternator 4 Battery 5 Capacitor 6 Control ECU
7 Current sensor 8 Voltage sensor

Claims (3)

A vehicle power generation control device including a battery and an alternator,
A capacitor for energy storage that is provided in a state connected in parallel to the battery and is charged by the power generation output of the alternator;
Battery charge detection means for detecting the state of charge of the battery;
Capacitor voltage detection means for detecting the voltage of the capacitor;
When the battery charge detection means detects a charge amount greater than a predetermined value and the detection voltage of the capacitor voltage detection means is equal to or higher than a threshold on the high voltage side, the excitation current of the alternator is turned off and the alternator is generated. A vehicle power generation control device comprising: control means for controlling the load energy supply of the capacitor in a stopped state. The vehicle power generation control device according to claim 1,
In addition to the control means, when the detection voltage of the capacitor voltage detection means falls below the threshold on the low voltage side during the control of the power generation stop state of the alternator, the excitation current is turned on, and the power generation stop state A vehicle power generation control device comprising means for canceling the control and controlling load feeding by the power generation output of the alternator and charging of the capacitor. In the vehicle power generation control device according to claim 1 or 2,
The vehicle power generation control device according to claim 1, wherein the charge amount equal to or greater than the predetermined value is a fully charged charge amount.

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