JPH0925864A - Charging device for vehicle power supply capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce self-discharge during parking of a vehicle by providing a main charging means for charging a capacitor in the specific operating state of an engine before the stop operation of the engine, and a stand-by charging means for charging the capacitor at the rated voltage only for the specified time after detecting the stop operation of the engine. SOLUTION: In an electric circuit of a retarder device with an induction machine functioning as a motor at the time of starting an engine and at the time of accelerating a vehicle, a control device 20 makes the induction machine 3 function as a generator at the time of judging the braking time of the vehicle with a brake depressed. The braking performance of the vehicle is thereby heightened, and mechanical energy is recovered as electric energy to a capacitor 5 and a low pressure battery 9. At the time of ignition off, the idling operation of the engine is maintained, and the induction machine 3 is made function as the generator. A first inverter 4 is controlled to execute charging so that the generated voltage becomes the rated voltage of the capacitor 5, and after the lapse of specified time, the engine is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for a vehicle power supply capacitor.

[0002]

2. Description of the Related Art In recent years, a cage-type multiphase induction machine is arranged between an engine crankshaft and a transmission, and this induction machine functions as a generator during vehicle braking to recover mechanical energy as electric energy. A retarder device has been proposed which uses this electric energy at the time of engine start and vehicle acceleration to cause an induction machine to function as an electric engine and to be used as a starter and an acceleration assist device. The above-mentioned induction machine must generate a high torque in order to directly rotate the crankshaft at the time of starting the engine and accelerating the vehicle, and a high-voltage drive induction machine is used.

As a result, in such a retarder device, a high-voltage storage battery is usually used to store electric energy.
Instead of this, it is disclosed that a capacitor is used to reduce the weight and improve the utilization efficiency of electric energy.

[0004]

In the above-mentioned prior art, the capacitor is always charged by the last braking of the traveling vehicle when the vehicle is parked. However, even if the capacitor voltage after charging is sufficiently high, a large self-discharge may occur in a vehicle parking period of about one day, and at this time, the induction machine cannot function as a starter at engine startup. .

Therefore, an object of the present invention is to provide a charging device for a vehicle power supply capacitor, which can reduce self-discharge of the vehicle power supply capacitor while the vehicle is parked.

[0006]

According to a first aspect of the present invention, there is provided a charging device for a capacitor for a vehicle power supply according to the present invention. Mainly charging means for charging the capacitor at least in a specific engine operating state before an engine stop operation, and when parking a vehicle. An engine stop operation detecting means for detecting the engine stop operation, and a preliminary charging means for charging the capacitor with the rated voltage only for a predetermined time after the engine stop operation detecting means detects the engine stop operation. It is characterized by doing.

The operation of the vehicle capacitor charging device will be described. When the vehicle is parked, the main charging means charges the capacitor before the engine stop operation, and after the engine stop operation detecting means detects the engine stop operation, the reserve operation is performed. Since the charging means charges the capacitor at its rated voltage only for a predetermined time, it is possible to bring the capacitor close to the fully charged state even if the capacitor is not sufficiently charged when the engine stop operation is detected.

According to a second aspect of the present invention, there is provided a charging device for a vehicle capacitor according to the present invention, wherein the engine stopping operation detecting means detects an engine stopping operation in the vehicle power source charging device according to the first aspect. The first voltage value of the capacitor at the time of
Capacitor voltage measuring means for measuring a voltage value, and the first
Calculating means for calculating a voltage drop degree determined based on the voltage value and the second voltage value; and when the voltage drop degree calculated by the calculating means is less than or equal to a predetermined value, the preliminary charging means charges the capacitor. And a charging stopping means for stopping the charging.

The operation of this vehicle capacitor charging device will be described. In the vehicle power source capacitor charging device according to claim 1, the first voltage value of the capacitor during engine stop operation measured by the capacitor voltage measuring means. And the second voltage value after the lapse of a set time thereafter, the calculating means calculates the voltage drop degree, and the charging stopping means detects the engine stop operation when the voltage drop degree is less than or equal to a predetermined value. Then, it is determined that the capacitor is fully charged, and the charging of the capacitor by the preliminary charging means is stopped.

A vehicle capacitor charging apparatus according to a third aspect of the present invention is the vehicle capacitor charging apparatus according to the first or second aspect, wherein the preliminary charging means is at least for the predetermined time. It has an engine operating means for operating the engine only, and a generator driven by the engine operated by the engine operating means to charge the capacitor.

A vehicle capacitor charging apparatus according to a fourth aspect of the present invention is the vehicle capacitor charging apparatus according to the first or second aspect, wherein the preliminary charging means is at least for the predetermined time. It has a storage battery for charging the capacitor only.

[0012]

1 is a schematic diagram showing the configuration of a retarder device including a vehicle capacitor charging device according to the present invention. Reference numeral 1 is an internal combustion engine, 2 is a transmission, and a cage-type multiphase induction machine 3 is arranged between the internal combustion engine 1 and the transmission 2. In this induction machine 3, one end of a rotary shaft 3f is directly connected to the engine crankshaft, and the other end is directly connected to the transmission 2. The rotor core 3a arranged around the rotary shaft 3f is equipped with a cage winding 3b, and the stator core 3c is equipped with a low voltage winding 3d and a high voltage winding 3e.

FIG. 2 is a schematic diagram of an electric circuit of this retarder device. As shown in the figure, the high-voltage winding 3 of the induction machine 3
e is electrically connected via the first inverter 4 to the capacitor 5, the resistor 6 arranged in parallel with the capacitor 5 and the chopper 7 for controlling the energization thereof, and the low voltage winding 3d is
It is electrically connected to a DC low voltage battery 9 via the second inverter 8. A contactor 10 is provided between the second inverter 8 and the low voltage battery 9. The low voltage battery 9 is for supplying electricity to electric components of the vehicle.

The second inverter 8 is composed of a transistor and a diode, and when controlled to the charging side, the low voltage winding 3
It is possible to convert the alternating current generated in d into a direct current to charge the low voltage battery 9, and conversely to apply the voltage of the low voltage battery 9 to the low voltage winding 3d when controlled to the discharge side. It makes it possible. The first inverter 4 is also similar, but can change the voltage and frequency applied to the high voltage winding 3e to change the generated magnetic flux and the induction machine torque.

The controller 20 is for controlling the first and second inverters 4, 8, the chopper 7, and the contactor 10, and has a voltage Vh and a current I1 of the capacitor 5, a voltage Vl of the low voltage battery 9, and a high voltage winding. Current I2 of line 3e, rotor speed of induction machine 3, that is, engine speed N, transmission 2
The gear ratio i, the ignition signal S1 of the internal combustion engine 1, the accelerator opening θ in the vehicle, the brake oil pressure p, the ignition on signal S2, the starter on signal S3, the vehicle speed v, the brake switch signal S4 and the like are input.

The controller 20 judges that the engine is starting based on the input of the starter-on signal S3,
In order to reduce the load, the contactor 10 is turned off, the magnetic flux φ generated in the high voltage winding 3e is maximized, and the optimum torque T corresponding to the engine speed N is generated so that the first inverter 4 is generated.
Is controlled to use the electric energy charged in the capacitor 5 to cause the induction machine 3 to function as an electric motor and to be used as a starter. Also, the accelerator opening θ
When it is determined that the vehicle is accelerating based on the change amount of
The first inverter 4 is controlled so that the optimum torque is generated based on the vehicle speed v, the gear ratio i, the engine speed N, etc., and the induction machine 3 also functions as an electric motor at this time to perform acceleration assist. ing.

Further, when it is determined that the vehicle is being braked with the brake being depressed based on the input of the brake switch signal S4, the induction machine 3 is caused to function as a generator to enhance the braking performance of the vehicle, and The mechanical energy discharged as brake heat is recovered as electric energy in the capacitor 5 and the low voltage battery 9. In this case, when the vehicle speed v is relatively high, the voltage generated by the low-voltage winding 3d may exceed the allowable voltage Ve of the electric component, and the contactor 10 is turned off to stop charging the low-voltage battery 9. The magnetic flux φ generated in the high-voltage winding 3e of the induction machine 3 is maximized to obtain the maximum braking force, and the optimum torque T is generated in the induction machine 3 based on the brake oil pressure p and the gear ratio i of the transmission 2. In order to prevent the capacitor 5 from being overcharged, the chopper 7 is controlled based on the voltage Vh of the capacitor 5 in order to discharge the excess current by the heat generation of the resistor 6. It is like this.

On the other hand, when the vehicle speed v becomes slow, the low-voltage battery 9 can be charged, so that the contactor 10 can be charged.
Is turned on, and the magnetic flux φ generated by the high-voltage winding 3e determined in consideration of the engine speed N so that the charging current becomes a predetermined voltage Ve lower than the allowable voltage of the electrical equipment is realized, and the induction machine 3 The first inverter 4 is controlled so as to generate the optimum torque T.

The control device 20 is configured to execute charging according to the first flow chart shown in FIG. 3 in addition to the charging / discharging of such a general capacitor 5. First, in step 101, it is judged whether or not the ignition on signal S2 is inputted, and when this judgment is affirmative, the processing is ended as it is, but when it is denied, it is when the ignition is turned off and the engine stopping step is executed. 1
02, when the driver intends to park the vehicle,
The engine idle operation is maintained, the induction machine 3 is made to function as a generator, and the first inverter 4 is controlled so that the generated voltage becomes the rated voltage of the capacitor 5 to execute charging.

Next, the process proceeds to step 103 and step 1
The elapsed time t from the start of charging 02 is a predetermined time t
It is judged whether it has reached 0 (for example, several minutes),
The charging in step 102 is executed until this determination is affirmed. On the other hand, when the elapsed time t reaches the predetermined time t0, the routine proceeds to step 104, the engine is stopped, and the charging of the capacitor 5 by the induction machine 3 is also ended accordingly. As described above, the control device 20 is configured to charge the capacitor 5 at the rated voltage only for a predetermined time after the ignition is turned off, that is, after the engine stop operation.

As shown in FIG. 4 which is an equivalent circuit diagram of the capacitor 5, a resistor R between terminals and a combination of a large number of minute capacitors cn and resistors rn arranged in series are arranged in parallel. It seems to be. The resistance value of each of these resistances rn is microscopically different, whereby the resistance rn having a small resistance value when the capacitor 5 is charged.
The micro capacitors cn arranged in series are sequentially charged.

As described above, the capacitor 5 is charged by the final vehicle braking when the vehicle is parked, and the electric energy is not used by the induction machine 3 thereafter. However, due to this charging, even if the voltage of the capacitor 5 is at its rated voltage, all of the minute capacitors cn may not be sufficiently charged. If left in that state, the self-discharge characteristics of the capacitor 5 may be reduced. As shown by the dotted line in FIG. 5 shown in FIG. 5, self-discharge occurs from a fully charged microcapacitor to an undercharged microcapacitor, and the voltage of the capacitor 5 drops considerably even when the vehicle is parked for about a day. However, the induction machine 3 may not be able to function as a starter at the next engine start. However, according to the present embodiment, the capacitor 5 is charged at the rated voltage only for a predetermined time after the engine stop operation when the vehicle is parked. For this reason, almost all of the minute capacitors forming the capacitor 5 are sufficiently charged, and as shown by the solid line in FIG. It is possible to considerably suppress the voltage drop due to self discharge during.

FIG. 6 is a second flowchart executed by the control device 20 in place of the first flowchart of FIG. First, in step 201, it is determined whether or not the ignition-on signal S2 is input, and when the determination is affirmative, the process ends, but when the determination is negative, the process proceeds to step 202 and the driver intends to park the vehicle. Then, the engine is stopped, and in step 203, the current first voltage V1 of the capacitor 5 is measured.

Next, in step 204, after a lapse of a set time from the measurement of the first voltage V1 (for example, 1 hour)
Measuring the second voltage V2 of the capacitor 5 of
5, the voltage drop degree D (= 1−V2 / V1) is calculated based on the first voltage V1 and the second voltage V2, and step 2
At 06, it is judged whether or not the voltage drop degree D is larger than the predetermined value D0. When this judgment is denied, the capacitor 5 is sufficiently charged during the engine stop operation as shown by the solid line in FIG. In order to prevent overcharging, further charging is not performed and the processing ends.

On the other hand, when the determination in step 206 is affirmative, the capacitor 5 is turned off when the engine is stopped.
Is not sufficiently charged, the process proceeds to step 207, and since the low voltage winding 3d and the high voltage winding 3e of the induction machine 3 are configured like a transformer, the first inverter 4 is charged on the charging side. In addition, the second inverter 8 is set to the discharging side, charging of the low-voltage battery 9 to the capacitor 5 at the rated voltage is started, and whether the elapsed time t from the start of charging reaches the predetermined time t0 in step 208. It is determined whether or not, and the charging in step 207 is continued until this determination is affirmed, and thereafter, the charging from the low voltage battery 9 is terminated in step 209.

As described above, by performing the further charging of the capacitor 5 only when the charging of the capacitor 5 is insufficient during the engine stop operation, the overcharging of the capacitor 5 is prevented and the self charging of the capacitor 5 during vehicle parking is prevented. It is possible to suppress the voltage drop due to discharge. In such charging of the capacitor 5, so-called pre-charging, at least a certain amount of charging of the capacitor is performed by the main charging before the engine stop operation, so that almost no current flows and the power loss of the low voltage battery 9 is extremely low. It is a small one.

FIG. 7 is a modification of the first flowchart of FIG. 3, in which the low voltage battery 9 is used instead of using the induction machine 3 as the precharging means for the capacitor, and the engine is stopped when the vehicle is stopped. Thus, the low voltage battery 9 charges the capacitor 5 only for a predetermined time. FIG. 8 is a modification of the second flowchart of FIG. 6, in which the induction machine 3 is used instead of using the low voltage battery 9 as the pre-charging means for the capacitor, and the engine is stopped during the engine stop operation. Then, the voltage drop degree of the capacitor 5 is calculated, and when this indicates a charging failure of the capacitor, the engine is operated again and the capacitor 5 is charged by the induction machine 3.

In the embodiment described above, the induction machine 3 has two types of windings in order to also charge the low-voltage battery 9, so that in the pre-charging of the capacitor from the low-voltage battery described above, Although these two kinds of windings are made to function like a transformer, in the case where the low voltage battery 9 is charged by an alternator as usual, the D for connecting the capacitor 5 and the low voltage battery 9 is used for this preliminary charging.
A C-DC converter is required. In addition, the capacitor 5
Have described that the induction machine functions as a starter at the time of engine startup, but this does not limit the present invention. It can also be used to energize a catalytic converter. Further, although the induction machine 3 of the retarder device or the low voltage battery 9 for vehicle electrical components is used for precharging the capacitor, of course, a generator or a battery driven by an engine may be provided for that purpose.

[0029]

As described above, according to the charging device for a capacitor for a vehicle power supply according to the present invention as set forth in claim 1, the main charging means charges the capacitor before the engine is stopped and the engine is stopped when the vehicle is parked. After the engine stopping operation is detected by the detecting means, the pre-charging means charges the capacitor at its rated voltage only for a predetermined time, so that the capacitor is not sufficiently charged at the time when the engine stopping operation is detected. However, it is possible to bring it closer to the fully charged state, and the amount of self-discharge that charges move between minute capacitors of the capacitors decreases while the vehicle is parked, and the amount of voltage drop of the capacitors at the next engine start is considerably reduced. Can be suppressed. Further, this self-discharge has a large energy loss and is accompanied by heat generation. Therefore, by reducing it, the durability of the capacitor can be improved.

According to a second aspect of the present invention, there is provided a vehicle capacitor charging apparatus according to the present invention. In the vehicle power source capacitor charging apparatus according to the first aspect, the engine stop operation measured by the capacitor voltage measuring means is performed. Based on the first voltage value of the capacitor at the time and the second voltage value after the lapse of the set time thereafter, the calculating means calculates the voltage drop degree, and the charging stopping means, when the voltage drop degree is less than or equal to the predetermined value, When the engine stop operation is detected, it is determined that the capacitor is in a fully charged state, and the charging of the capacitor by the precharging means is stopped. Therefore, overcharging of the capacitor is prevented and unnecessary energy loss by the precharging means is prevented. You can

According to the vehicle capacitor charging device of the present invention as defined in claim 3, in the vehicle capacitor charging device of claim 1 or 2, the pre-charging means is at least for a predetermined time. It is also possible to use this generator as the main charging means, since it has an engine operating means for operating the engine only and a generator driven by the engine operated by the engine operating means to charge the capacitor.

According to the vehicle capacitor charging device of the present invention as defined in claim 4, in the vehicle capacitor charging device of claim 1 or 2, the pre-charging means is at least for a predetermined time. Since it has a storage battery that only charges the capacitor, it is not necessary to operate the engine after the engine stop operation.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a retarder device including a vehicle capacitor charging device according to the present invention.

2 is a schematic diagram of an electric circuit of the retarder device of FIG. 1. FIG.

FIG. 3 is a first flow chart for capacitor charging performed by the controller.

FIG. 4 is an equivalent circuit diagram of a capacitor.

FIG. 5 is a graph showing a self-discharge characteristic of a capacitor.

FIG. 6 is a second flow chart for capacitor charging performed by the controller.

FIG. 7 is a third flowchart for capacitor charging performed by the controller.

FIG. 8 is a fourth flowchart for capacitor charging executed by the control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Transmission 3 ... Cage type multi-phase induction machine 3d ... Low voltage winding 3e ... High voltage winding 3f ... Rotating shaft 4 ... 1st inverter 5 ... Capacitor 8 ... 2nd inverter 9 ... Low voltage battery

Claims (4)

[Claims] 1. Main charging means for charging a capacitor at least in a specific engine operating state before an engine stop operation,
An engine stop operation detecting means for detecting an engine stop operation when the vehicle is parked, and a pre-charging means for charging the capacitor at its rated voltage only for a predetermined time after the engine stop operation is detected by the engine stop operation detecting means, A charging device for a capacitor for a vehicle power supply, comprising: 2. A capacitor voltage measuring means for measuring a first voltage value of the capacitor when an engine stop operation is detected by the engine stop operation detecting means and a second voltage value after a lapse of a set time from that time, and Calculating means for calculating a voltage drop degree determined based on the first voltage value and the second voltage value; and when the voltage drop degree calculated by the calculating means is a predetermined value or less, The charging device for a vehicle power supply capacitor according to claim 1, further comprising: a charging stopping unit that stops charging. 3. The pre-charging means has an engine operating means for operating the engine at least for the predetermined time, and a generator driven by the engine operated by the engine operating means to charge the capacitor. The charging device for a vehicle capacitor according to claim 1 or 2, characterized in that. 4. The charging device for a vehicle capacitor according to claim 1, wherein the preliminary charging means has a storage battery that charges the capacitor at least for the predetermined time.