Title of Invention	A VOLTAGE BOOSTER FOR ENGINE GENERATOR AND A METHOD FOR CONTROL OF THE VOLTAGE BOOSTER
Abstract	A voltage booster for engine generator comprising an engine ignition apparatus of the full transistor igniter method capable of igniting the engine by the kick method. Between a voltage adjusting device receiving a start current from the kick-driven generator and an electronic device such as an ECU connected to the voltage adjusting device, there is connected in parallel an active boosting circuit performing boosting operation only during output of a low voltage of the voltage adjusting device upon engine start by kick and terminating the boosting operation when the stationary operation is set in after the engine start. A control method of the voltage booster is also disclosed.

Title of Invention

A VOLTAGE BOOSTER FOR ENGINE GENERATOR AND A METHOD FOR CONTROL OF THE VOLTAGE BOOSTER

Abstract

A voltage booster for engine generator comprising an engine ignition apparatus of the full transistor igniter method capable of igniting the engine by the kick method. Between a voltage adjusting device receiving a start current from the kick-driven generator and an electronic device such as an ECU connected to the voltage adjusting device, there is connected in parallel an active boosting circuit performing boosting operation only during output of a low voltage of the voltage adjusting device upon engine start by kick and terminating the boosting operation when the stationary operation is set in after the engine start. A control method of the voltage booster is also disclosed.

Full Text	DESCRIPTION VOLTAGE BOOSTER FOR ENGINE GENERATOR AND CONTROL METHOD THEREOF TECHNICAL FIELD The present invention relates to a voltage booster for engine generator and control method thereof. BACKGROUND ART Conventionally, a motor bicycle uses as an engine start ignition circuit the CDI (capacitor discharge igniter) method and the full transistor igniter method. Here, the CDI can operate regardless of presence/absence of a battery and can perform engine start by a so-called kick method. However, the CDI has a problem that it is inferior to the full transistor igniter method when igniting a dilute air-fuel mixture. Moreover, the full transistor igniter method is appropriate for energy saving such as optimal ignition control of engine but requires a battery and cannot start an engine by the kick method. Explanation will be given on an outline of the conventional full transistor igniter circuit with reference to Fig. 1. The full transistor igniter circuit includes a generator 1, a voltage adjusting unit 2, a battery 8, a lamp 3, an engine control unit (ECU) 4, an igniter 5, an injector 6, a fuel pump 7, and other DC load 9 connected in parallel. In this conventional full transistor igniter circuit, when a main switch 11 is such as a starter button is closed, voltage from the battery 8 is supplied to the entire circuit to operate the ECU 4 and relays 10, 40 are closed to start the engine. However, even if the generator 1 is provided with means of the kick method as a countermeasure when the battery is dead, the low rotation of the generator 1 obtained by the kick cannot supply stable voltage to electronic parts such as the ECU 4 from the voltage adjusting unit 2. As a result, in the conventional full transistor igniter method, the engine start by the kick method is extremely difficult and substantially cannot start drive. DISCLOSURE OF THE INVENTION It is therefore an object of the present invention to provide a voltage booster for engine generator capable of starting engine by the so-called kick method and control method thereof. In order to achieve the aforementioned object, in the voltage booster for engine generator according to the present invention, between a voltage adjusting device receiving a start current from the generator driven by the kick method and a load such as an ECU connected to the voltage adjusting device, there is connected an active boosting circuit for boosting voltage while the voltage adjusting device outputs a low voltage upon engine start by the kick method and terminating the boosting operation when the stationary operation is set in after the engine start. Only upon engine start, the output of the voltage adjusting device is boosted by the active boosting circuit and supplied to a load such as the ECU. Moreover, the present invention provides a control method for the voltage booster for engine generator. In the voltage booster for engine generator including a load such as an ECU connected to a voltage adjusting device receiving a start current from the generator driven by the kick method, the output voltage output from the voltage adjusting device is compared to the operation voltage of the engine stationary operation and boosting adjustment is performed until the output voltage reaches the operation voltage of the stationary operation. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows an outline of an engine ignition circuit of the conventional full transistor igniter method. Fig. 2 shows configuration of a voltage booster for engine generator according to an embodiment of the present invention. Fig. 3 shows detailed configuration of a DC/DC converter in Fig. 2. Fig. 4 shows detailed configuration of a DC/DC converter according to another embodiment. Fig. 5 shows detailed configuration of a DC/DC converter according to still another embodiment. Fig. 6 shows detailed configuration of a DC/DC converter according to yet another embodiment. Fig. 7 shows detailed configuration of a DC/DC converter according to still yet another embodiment. BEST MODE FOR CARRYING OUT THE INVENTION Description will now be directed to a voltage booster for engine generator and control method thereof according to embodiments of the present invention with reference to the attached drawings. Fig. 2 shows the entire configuration of the voltage booster for engine generator according to the present invention. Like components as in the conventional example shown in Fig. 1 are denoted by like reference symbols and their detailed explanations are omitted. The voltage booster for engine generator of Fig. 2 is characterized in that the DC/DC converter 20 is connected as an active booster circuit between the voltage adjustment unit (REG) 2 and the electronic device such as the ECU 4 connected to the REG 2 to receive voltage. Moreover, the battery 8 shown in the figure is in the discharge state below a predetermined start voltage upon start by the kick method as an object of the present invention and it is assumed that the generator 1 is driven by the so-called kick method. After the engine reaches a stationary rotation, the battery 8 is charged and afterwards, the engine can be started by the battery 8. Moreover, in the circuit shown in Fig. 2, a diode 39 is inserted between the DC/DC converter 20 and the battery 8, so as to prevent flow in of current to the side of the battery 8 having a large current capacity upon boosting of the DC/DC converter 20. Furthermore, Fig. 3 shows detailed configuration of this DC/DC converter 20. In Fig. 3, the DC/DC converter basically consists of a diode 23, a coil 24, and a diode 25 which are connected in series and a capacitor 26, a transistor 27, and a capacitor 30 which are connected between the series connection and the ground line. Furthermore, in addition to this basic structure, a bypass circuit 21 consisting of a diode 22 connected in parallel between the diodes 23 and 25 is provided. Furthermore, a feedback circuit 32 including a Zener diode 30 is arranged. Furthermore, the output of the feedback circuit 32 is connected to an oscillation circuit 31. This oscillation circuit 31 is configured so as to supply a drive signal to the base of the transistor 27 via a resistor 28. In the DC/DC converter 20 having such a configuration, the control voltage VI of the REG 2 (output fluctuating depending on the rpm of the generator) is compared to the control voltage V2 of the DC/DC converter 20 (a reference voltage such as 12V at which the engine performs stationary rotation and the electronic devices operate normally). That is, when the control voltage VI of the REG 2 by a low rpm at rotation start by turning on the main switch 11 and kicking the ACG 1 is lower than the control voltage V2 of the DC/DC converter 20 (VI When the reference voltage V2 boosted by the DC/DC converter 20 is output, the ECU 4 operates and the engine starts operation. With this engine start, the ACG 1 is driven by the engine to increase the rpm. When the ACG 1 reaches the stationary rotation, the voltage applied to the Zener diode 30 via the bypass circuit 21 is increased step by step to a value equal to or above V2 when subtracted by the voltage drop of the diode 22. At this moment, a voltage equal to or above 2V which is the preset output of the DC/DC convert 20 is detected by the feedback circuit 32 (VI > V2) . Then, the feedback circuit 32 transmits a feedback signal so as to stop drive output of the oscillation circuit 31 to the transistor 27. The boosting operation of the DC/DC converter 20 stops. The control voltage VI of the REG 2 which has become equal to or above the control voltage V2 of the DC/DC converter 20 is bypassed by the diode 22 of the bypass circuit 21 and supplied dtc the electronic circuits such as the ECU 4. Furthermore, the relays 10, 40 are closed and a reference voltage is applied to the DC load 9, thereby starting charge of the battery 8. After this, the engine performs stationary rotation and the ACG 1 generates above the nominal output. In the REG 2, the output voltage of the stationary operation is obtained and supplied via the bypass circuit 21 to the ECU 4 and other electronic devices. In the embodiment shown in Fig. 3, the bypass circuit 21 is composed of a diode but it can also be replaced by a resistor. Moreover, the oscillation circuit 31 may be configured to oscillate stationary drive frequency such as 50 KHz and cut off the DC/DC converter circuit by the relay using a signal of the feedback circuit 32 instead of using control of PWM and PFM. Next, explanation will be given on the DC/DC converter 20 of Fig. 4 according to another embodiment. In this embodiment, the bypass circuit 21 is composed of a relay 34 and a control circuit 34 is provided to operate the relay 34. This control circuit 33 includes a Zener diode 38 for monitoring voltage VI arranged at the input side of the DC/DC converter 20. When the control voltage VI of the REG 2 has become greater than the control output V2 of the DC/DC converter 20 (VI > V2), the relay 34 is turned on, oscillation of the oscillation circuit 31 stops, and the DC/DC converter 20 is bypassed by the bypass circuit 21. When the relay 34 is closed by the operation of the control circuit 33, the voltage change of VI > V2 is detected by the feedback circuit 32 and boosting operation of the DC/DC convert 20 is terminated. Moreover, this control circuit 33 may be replaced by a timer circuit controlling ON/OFF of the relay 34 after a sufficient time when the VI becomes greater than V2 after the start by the kick method, or may be replaced by a switching element such as a transistor. Moreover, it is possible to turn ON/OFF when the value of VI reaches the stationary rotation value regardless of the value of V2. Furthermore, in the embodiment of Fig. 5, a relay 34 is provided at the input side of the diode 23 instead of the bypass circuit 21, so as to be operated by the control circuit 33 similar to the one in Fig. 4. In this configuration, the engine is normally started by the kick when the relay 34 is closed. When the control voltage VI of the REG 1 has become equal to or greater than the control voltage V2 of the DC/DC converter 20 (VI > V2), the control circuit 323 operates to open the relay 34, so that the DC/DC converter 20 itself enters a stop state. As shown in Fig. 2, VI equal to or greater than V2 is supplied to the electronic devices such as ECU 5 connected in parallel to the REG 2 and the operation is maintained. In the embodiment of Fig. 5 also, the control circuit 33 monitors the control voltage V2 of the DC/DC converter, or it may be replaced by a timer operating after a lapse of a predetermined period of time. The relay may be replaced by the switching element such as a transistor. Moreover, after the relay 34 is opened and the boosting operation of the DC/DC converter 20 stops, the engine performs the stationary operation and the stationary voltage from the REG 2 obtained by the stationary operation of the engine closes the relay 10, so that the stationary voltage is applied to all the circuit components shown in Fig. 2. In this configuration also, it is possible to employ a relay operating upon voltage of the stationary rotation regardless of the value of V2. Furthermore, in the embodiment shown in Fig. 6, the oscillation circuit 31 boosts the control voltage VI from the REG 2 to a predetermined voltage V2 by the feedback signal from the feedback circuit 32. Furthermore, an oscillation circuit 35 consisting of a resistor 36 and a transistor 37 is provided for terminating the operation of the transistor 27. This oscillation stop circuit 35 is controlled by a control circuit 33 having a Zener diode 38 for detecting the voltage VI of the input side of the DC/DC converter 20. The control circuit 33 terminates the operation of the transistor 27 under the condition of VI > V2 in the same way as the embodiment of Fig. 3 and substantially terminates the operation of the DC/DC converter 20. In this embodiment also, the control circuit 33 may directly monitor the voltage VI or timer operation can be used to terminate the oscillation stop circuit 35. In this configuration also, it is possible to employ a relay operating upon a voltage of stationary rotation regardless of the value of V2. Furthermore, in the embodiment shown in Fig. 7, as compared to the embodiment of Fig. 3, the oscillation circuit 31 performs feedback control by the feedback circuit 32 and a bypass circuit 21 consisting of a diode 22 is provided in parallel. In the same way as the embodiment of Fig. 3, the feedback circuit 32 monitors the control voltage VI of the REG 2 and upon detection of VI > V2, the control circuit 33 operates the oscillation stop circuit 35. Thus, after stop of bossing operation of the DC/DC converter 20, the engine performs stationary operation and the stationary voltage from the REG 2 operates the oscillation stop circuit 35, so that the stationary voltage is applied to all the circuit components shown in Fig. 2. Furthermore, in this configuration also, it is possible to use an oscillation stop circuit operating upon a voltage of the stationary rotation regardless of the value of V2. INDUSTRIAL APPLICABILITY As has been described above, the voltage booster for engine generator and control method thereof according to the present invention enables the engine ignition circuit of the full transistor igniter method to start the engine by the so-called kick method even when the battery is in a discharge state. CLAIMS 1. A voltage booster for an engine generator which is an engine ignition apparatus of the full transistor igniter method, comprising: a generator which can be driven by the kick method, a voltage adjusting device connected to the generator and adjusting voltage of power supplied from the generator, an electronic device connected to the voltage adjusting device and controlling ignition/operation control of the engine by voltage supplied from the voltage adjusting device, and an active boosting circuit connected between the voltage adjusting device and the electronic device, boosting the output voltage of the voltage adjusting device to a predetermined nominal voltage of the electronic device upon the engine start by kicking the generator when the power supply is lower than the predetermined engine stationary operation, and stopping the boosting operation when the output voltage from the voltage adjusting device has become the predetermined nominal voltage of the engine stationary operation, and said active boosting circuit further includes a condenser for charging electromotive force at least by said kick. 2. ¦ • A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having: a feedback circuit for performing feedback so that the voltage of the output side becomes the predetermined nominal voltage, said condenser is inserted between said feedback circuit and said output side, and a bypass circuit for bypassing from the input side to the output side of the active boosting circuit by a predetermined voltage drop, and the feedback circuit stops boosting operation of the DC/DC converter when the voltage VI of the input side bypassed to the output side of the DC/DC converter which is subtracted by voltage drop of the bypass circuit exceeds a predetermined nominal voltage V2 (VI - voltage drop of bypass circuit > V2). 3. A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having: a feedback circuit for performing feedback so that the voltage of the output side becomes the predetermined nominal voltage, said condenser is inserted between said feedback circuit and said output side, and a bypass circuit having a relay which is normally open and bypassing from the input side to the output side of the active boosting circuit, and a control circuit for detecting the voltage of the input side of the active boosting circuit and closing the relay which is normally open, and at the moment when the voltage VI of the input side has become a predetermined voltage from the voltage adjusting device during the stationary operation, the control circuit closes the relay so as to stop the boosting operation of the DC/DC converter. 4. A voltage booster for engine generator as claimed in Claim 3, wherein the moment of the predetermined voltage is a moment when the predetermined nominal voltage V2 is exceeded (VI > V2), and the relay is closed at this moment, and the feedback circuit stops the boosting operation of the DC/DC converter when the voltage VI of the input side bypassed by the output side of the DC/DC converter exceeds the predetermined nominal voltage (VI > V2). 5. A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having: a feedback circuit for performing feedback so that the voltage of the output side becomes the predetermined nominal voltage, said condenser is inserted between said feedback circuit and said output side, and a relay which is provided at the input side and normally closed, and a control circuit for operating the relay according to the voltage VI at the input side of the active boosting circuit, and the control circuit opens the relay at the moment when the voltage VI of the input side has become a predetermined voltage from the voltage adjusting device during stationary operation so as to stop the boosting operation of the DC/DC converter. 6. A voltage booster for engine generator as claimed in Claim 5, wherein the moment when the predetermined voltage is obtained is the moment when the voltage has become equal to or above the nominal voltage V2 (VI > V2) and at this moment the relay is opened. 7. A voltage booster for engine generator as claimed in Claim 6, wherein the active boosting circuit is a DC/DC converter having: a feedback circuit for performing feedback so that the voltage of the output side is the predetermined nominal voltage V2, and a control circuit for detecting the voltage VI of the input side of the active boosting side so as to stop the boosting operation, and at the moment when the voltage VI of the input side has become a predetermined voltage from the voltage adjusting device during the stationary operation, the control circuit stops the oscillation stop circuit and stops the boosting operation of the DC/DC converter. 8. A voltage booster for engine generator as claimed in Claim 7, wherein the moment when the predetermined voltage is obtained is the moment when the voltage is equal to or above the nominal voltage (VI > V2) and at this moment operation of the DC/DC converter is stopped. 9. A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having: voltage V2 (VI > V2) and at this moment the relay is a feedback circuit for performing feedback so that the voltage of the output side becomes the predetermined nominal voltage V2, said condenser is inserted between said feedback circuit and said output side, and a bypass circuit bypassing from the input side to the output side of the active boosting circuit by a predetermined voltage drop, and a control circuit for terminating operation of the active boosting circuit by the output of the feedback circuit, and at the moment when the voltage VI of the input side bypassed to the output side has become a predetermined voltage from the voltage adjusting device during the stationary operation, the feedback circuit stops the boosting operation of the DC/DC converter. 10. A voltage booster for engine generator as claimed in Claim 9, wherein the predetermined moment is the moment when the voltage has exceeded the nominal voltage V2 and at this moment boosting operation of the DC/DC converter is stopped. 11. . - *¦ An ignition control method for an engine ignition apparatus of the full transistor igniter method having a battery and a generator which can be driven by the kick method, the method comprising steps of: boosting voltage driven by a kick to a predetermined nominal voltage of the stationary operation of the ignition apparatus by sequential charging while a low voltage of a generator insufficient for engine stationary operation is output and applying the boosted voltage to the ignition apparatus, and terminating the boosting operation when the voltage has become equal to or above the voltage of stationary operation and applying the output voltage of the generator directly to the ignition apparatus. A voltage booster for engine generator comprising an engine ignition apparatus of the full transistor igniter method capable of igniting the engine by the kick method. Between a voltage adjusting device receiving a start current from the kick-driven generator and an electronic device such as an ECU connected to the voltage adjusting device, there is connected in parallel an active boosting circuit performing boosting operation only during output of a low voltage of the voltage adjusting device upon engine start by kick and terminating the boosting operation when the stationary operation is set in after the engine start. A control method of the voltage booster is also disclosed.

Full Text

DESCRIPTION
VOLTAGE BOOSTER FOR ENGINE GENERATOR AND
CONTROL METHOD THEREOF
TECHNICAL FIELD
The present invention relates to a voltage booster for engine generator and control method thereof.
BACKGROUND ART
Conventionally, a motor bicycle uses as an engine start ignition circuit the CDI (capacitor discharge igniter) method and the full transistor igniter method. Here, the CDI can operate regardless of presence/absence of a battery and can perform engine start by a so-called kick method. However, the CDI has a problem that it is inferior to the full transistor igniter method when igniting a dilute air-fuel mixture. Moreover, the full transistor igniter method is appropriate for energy saving such as optimal ignition control of engine but requires a battery and cannot start an engine by the kick method.
Explanation will be given on an outline of the conventional full transistor igniter circuit with reference to Fig. 1. The full transistor igniter circuit includes a generator 1, a voltage adjusting unit 2, a battery 8, a lamp 3, an engine control unit
(ECU) 4, an igniter 5, an injector 6, a fuel pump 7, and other DC load 9 connected in parallel. In this conventional full transistor igniter circuit, when a main switch 11 is such as a starter button is closed, voltage from the battery 8 is supplied to the entire circuit to operate the ECU 4 and relays 10, 40 are closed to start the engine. However, even if the generator 1 is provided with means of the kick method as a countermeasure when the battery is dead, the low rotation of the generator 1 obtained by the kick cannot supply stable voltage to electronic parts such as the ECU 4 from the voltage adjusting unit 2. As a result, in the conventional full transistor igniter method, the engine start by the kick method is extremely difficult and substantially cannot start drive.
DISCLOSURE OF THE INVENTION
It is therefore an object of the present invention to provide a voltage booster for engine generator capable of starting engine by the so-called kick method and control method thereof.
In order to achieve the aforementioned object, in the voltage booster for engine generator according to the present invention, between a voltage adjusting device receiving a start current from the generator driven by the kick method and a load such as an ECU connected to the voltage adjusting device, there is connected an active boosting circuit for boosting
voltage while the voltage adjusting device outputs a low voltage upon engine start by the kick method and terminating the boosting operation when the stationary operation is set in after the engine start. Only upon engine start, the output of the voltage adjusting device is boosted by the active boosting circuit and supplied to a load such as the ECU.
Moreover, the present invention provides a control method for the voltage booster for engine generator. In the voltage booster for engine generator including a load such as an ECU connected to a voltage adjusting device receiving a start current from the generator driven by the kick method, the output voltage output from the voltage adjusting device is compared to the operation voltage of the engine stationary operation and boosting adjustment is performed until the output voltage reaches the operation voltage of the stationary operation.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows an outline of an engine ignition circuit of the conventional full transistor igniter method.
Fig. 2 shows configuration of a voltage booster for engine generator according to an embodiment of the present invention.
Fig. 3 shows detailed configuration of a DC/DC converter in Fig. 2.
Fig. 4 shows detailed configuration of a DC/DC converter according to another embodiment.
Fig. 5 shows detailed configuration of a DC/DC converter according to still another embodiment.
Fig. 6 shows detailed configuration of a DC/DC converter according to yet another embodiment.
Fig. 7 shows detailed configuration of a DC/DC converter according to still yet another embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
Description will now be directed to a voltage booster for engine generator and control method thereof according to embodiments of the present invention with reference to the attached drawings.
Fig. 2 shows the entire configuration of the voltage booster for engine generator according to the present invention. Like components as in the conventional example shown in Fig. 1 are denoted by like reference symbols and their detailed explanations are omitted. The voltage booster for engine generator of Fig. 2 is characterized in that the DC/DC converter 20 is connected as an active booster circuit between the voltage adjustment unit (REG) 2 and the electronic device such as the ECU 4 connected to the REG 2 to receive voltage. Moreover, the battery 8 shown in the figure is in the discharge state below a predetermined start voltage upon start by the kick method as an
object of the present invention and it is assumed that the generator 1 is driven by the so-called kick method. After the engine reaches a stationary rotation, the battery 8 is charged and afterwards, the engine can be started by the battery 8. Moreover, in the circuit shown in Fig. 2, a diode 39 is inserted between the DC/DC converter 20 and the battery 8, so as to prevent flow in of current to the side of the battery 8 having a large current capacity upon boosting of the DC/DC converter 20.
Furthermore, Fig. 3 shows detailed configuration of this DC/DC converter 20. In Fig. 3, the DC/DC converter basically consists of a diode 23, a coil 24, and a diode 25 which are connected in series and a capacitor 26, a transistor 27, and a capacitor 30 which are connected between the series connection and the ground line.
Furthermore, in addition to this basic structure, a bypass circuit 21 consisting of a diode 22 connected in parallel between the diodes 23 and 25 is provided. Furthermore, a feedback circuit 32 including a Zener diode 30 is arranged. Furthermore, the output of the feedback circuit 32 is connected to an oscillation circuit 31. This oscillation circuit 31 is configured so as to supply a drive signal to the base of the transistor 27 via a resistor 28.
In the DC/DC converter 20 having such a configuration, the control voltage VI of the REG 2
(output fluctuating depending on the rpm of the generator) is compared to the control voltage V2 of the DC/DC converter 20 (a reference voltage such as 12V at which the engine performs stationary rotation and the electronic devices operate normally). That is, when the control voltage VI of the REG 2 by a low rpm at rotation start by turning on the main switch 11 and kicking the ACG 1 is lower than the control voltage V2 of the DC/DC converter 20 (VI When the reference voltage V2 boosted by the DC/DC converter 20 is output, the ECU 4 operates and the engine starts operation. With this engine start, the ACG 1 is driven by the engine to increase the rpm. When the ACG 1 reaches the stationary rotation, the
voltage applied to the Zener diode 30 via the bypass circuit 21 is increased step by step to a value equal to or above V2 when subtracted by the voltage drop of the diode 22. At this moment, a voltage equal to or above 2V which is the preset output of the DC/DC convert 20 is detected by the feedback circuit 32 (VI > V2) .
Then, the feedback circuit 32 transmits a feedback signal so as to stop drive output of the oscillation circuit 31 to the transistor 27. The boosting operation of the DC/DC converter 20 stops. The control voltage VI of the REG 2 which has become equal to or above the control voltage V2 of the DC/DC converter 20 is bypassed by the diode 22 of the bypass circuit 21 and supplied dtc the electronic circuits such as the ECU 4. Furthermore, the relays 10, 40 are closed and a reference voltage is applied to the DC load 9, thereby starting charge of the battery 8.
After this, the engine performs stationary rotation and the ACG 1 generates above the nominal output. In the REG 2, the output voltage of the stationary operation is obtained and supplied via the bypass circuit 21 to the ECU 4 and other electronic devices. In the embodiment shown in Fig. 3, the bypass circuit 21 is composed of a diode but it can also be replaced by a resistor. Moreover, the oscillation circuit 31 may be configured to oscillate stationary drive frequency such as 50 KHz and cut off the DC/DC
converter circuit by the relay using a signal of the feedback circuit 32 instead of using control of PWM and PFM.
Next, explanation will be given on the DC/DC converter 20 of Fig. 4 according to another embodiment. In this embodiment, the bypass circuit 21 is composed of a relay 34 and a control circuit 34 is provided to operate the relay 34. This control circuit 33 includes a Zener diode 38 for monitoring voltage VI arranged at the input side of the DC/DC converter 20. When the control voltage VI of the REG 2 has become greater than the control output V2 of the DC/DC converter 20 (VI > V2), the relay 34 is turned on, oscillation of the oscillation circuit 31 stops, and the DC/DC converter 20 is bypassed by the bypass circuit 21. When the relay 34 is closed by the operation of the control circuit 33, the voltage change of VI > V2 is detected by the feedback circuit 32 and boosting operation of the DC/DC convert 20 is terminated. Moreover, this control circuit 33 may be replaced by a timer circuit controlling ON/OFF of the relay 34 after a sufficient time when the VI becomes greater than V2 after the start by the kick method, or may be replaced by a switching element such as a transistor. Moreover, it is possible to turn ON/OFF when the value of VI reaches the stationary rotation value regardless of the value of V2.
Furthermore, in the embodiment of Fig. 5, a
relay 34 is provided at the input side of the diode 23 instead of the bypass circuit 21, so as to be operated by the control circuit 33 similar to the one in Fig. 4. In this configuration, the engine is normally started by the kick when the relay 34 is closed. When the control voltage VI of the REG 1 has become equal to or greater than the control voltage V2 of the DC/DC converter 20 (VI > V2), the control circuit 323 operates to open the relay 34, so that the DC/DC converter 20 itself enters a stop state. As shown in Fig. 2, VI equal to or greater than V2 is supplied to the electronic devices such as ECU 5 connected in parallel to the REG 2 and the operation is maintained. In the embodiment of Fig. 5 also, the control circuit 33 monitors the control voltage V2 of the DC/DC converter, or it may be replaced by a timer operating after a lapse of a predetermined period of time. The relay may be replaced by the switching element such as a transistor. Moreover, after the relay 34 is opened and the boosting operation of the DC/DC converter 20 stops, the engine performs the stationary operation and the stationary voltage from the REG 2 obtained by the stationary operation of the engine closes the relay 10, so that the stationary voltage is applied to all the circuit components shown in Fig. 2. In this configuration also, it is possible to employ a relay operating upon voltage of the stationary rotation regardless of the value of V2.
Furthermore, in the embodiment shown in Fig.
6, the oscillation circuit 31 boosts the control voltage VI from the REG 2 to a predetermined voltage V2 by the feedback signal from the feedback circuit 32. Furthermore, an oscillation circuit 35 consisting of a resistor 36 and a transistor 37 is provided for terminating the operation of the transistor 27. This oscillation stop circuit 35 is controlled by a control circuit 33 having a Zener diode 38 for detecting the voltage VI of the input side of the DC/DC converter 20. The control circuit 33 terminates the operation of the transistor 27 under the condition of VI > V2 in the same way as the embodiment of Fig. 3 and substantially terminates the operation of the DC/DC converter 20. In this embodiment also, the control circuit 33 may directly monitor the voltage VI or timer operation can be used to terminate the oscillation stop circuit 35. In this configuration also, it is possible to employ a relay operating upon a voltage of stationary rotation regardless of the value of V2.
Furthermore, in the embodiment shown in Fig.
7, as compared to the embodiment of Fig. 3, the oscillation circuit 31 performs feedback control by the feedback circuit 32 and a bypass circuit 21 consisting of a diode 22 is provided in parallel. In the same way as the embodiment of Fig. 3, the feedback circuit 32 monitors the control voltage VI of the REG 2 and upon detection of VI > V2, the control circuit 33 operates
the oscillation stop circuit 35. Thus, after stop of bossing operation of the DC/DC converter 20, the engine performs stationary operation and the stationary voltage from the REG 2 operates the oscillation stop circuit 35, so that the stationary voltage is applied to all the circuit components shown in Fig. 2. Furthermore, in this configuration also, it is possible to use an oscillation stop circuit operating upon a voltage of the stationary rotation regardless of the value of V2.
INDUSTRIAL APPLICABILITY
As has been described above, the voltage booster for engine generator and control method thereof according to the present invention enables the engine ignition circuit of the full transistor igniter method to start the engine by the so-called kick method even when the battery is in a discharge state.
CLAIMS
1. A voltage booster for an engine generator which is an engine ignition apparatus of the full transistor igniter method, comprising:
a generator which can be driven by the kick method,
a voltage adjusting device connected to the generator and adjusting voltage of power supplied from the generator,
an electronic device connected to the voltage adjusting device and controlling ignition/operation control of the engine by voltage supplied from the voltage adjusting device, and
an active boosting circuit connected between the voltage adjusting device and the electronic device, boosting the output voltage of the voltage adjusting device to a predetermined nominal voltage of the electronic device upon the engine start by kicking the generator when the power supply is lower than the predetermined engine stationary operation, and stopping the boosting operation when the output voltage from the voltage adjusting device has become the predetermined nominal voltage of the engine stationary operation, and said active boosting circuit further includes a condenser for charging electromotive force at least by said kick.
2. ¦ • A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit
is a DC/DC converter having:
a feedback circuit for performing feedback so that the voltage of the output side becomes the
predetermined nominal voltage,
said condenser is inserted between said feedback circuit and said output side, and
a bypass circuit for bypassing from the input side to the output side of the active boosting circuit by a predetermined voltage drop,
and the feedback circuit stops boosting operation of the DC/DC converter when the voltage VI of the input side bypassed to the output side of the DC/DC converter which is subtracted by voltage drop of the bypass circuit exceeds a predetermined nominal voltage V2 (VI - voltage drop of bypass circuit > V2). 3. A voltage booster for engine generator as
claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having:
a feedback circuit for performing feedback so that the voltage of the output side becomes the predetermined nominal voltage,
said condenser is inserted between said feedback circuit and said output side, and
a bypass circuit having a relay which is normally open and bypassing from the input side to the output side of the active boosting circuit, and
a control circuit for detecting the voltage of the input side of the active boosting circuit and closing the relay which is normally open,
and at the moment when the voltage VI of the input side has become a predetermined voltage from the
voltage adjusting device during the stationary operation, the control circuit closes the relay so as to stop the boosting operation of the DC/DC converter. 4. A voltage booster for engine generator as
claimed in Claim 3, wherein the moment of the predetermined voltage is a moment when the predetermined nominal voltage V2 is exceeded (VI > V2), and the relay is closed at this moment, and the feedback circuit stops the boosting operation of the DC/DC converter when the voltage VI of the input side bypassed by the output side of the DC/DC converter exceeds the predetermined nominal voltage (VI > V2).
5. A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having:
a feedback circuit for performing feedback so that the voltage of the output side becomes the predetermined nominal voltage,
said condenser is inserted between said feedback circuit and said output side, and
a relay which is provided at the input side and normally closed, and
a control circuit for operating the relay according to the voltage VI at the input side of the active boosting circuit,
and the control circuit opens the relay at the moment when the voltage VI of the input side has become a predetermined voltage from the voltage adjusting device during stationary operation so as to stop the boosting operation of the DC/DC converter.
6. A voltage booster for engine generator as claimed in Claim 5, wherein the moment when the
predetermined voltage is obtained is the moment when the voltage has become equal to or above the nominal
voltage V2 (VI > V2) and at this moment the relay is opened.
7. A voltage booster for engine generator as claimed in Claim 6, wherein the active boosting circuit is a DC/DC converter having:
a feedback circuit for performing feedback so that the voltage of the output side is the predetermined nominal voltage V2, and
a control circuit for detecting the voltage VI of the input side of the active boosting side so as to stop the boosting operation,
and at the moment when the voltage VI of the input side has become a predetermined voltage from the voltage adjusting device during the stationary operation, the control circuit stops the oscillation stop circuit and stops the boosting operation of the DC/DC converter.
8. A voltage booster for engine generator as claimed in Claim 7, wherein the moment when the predetermined voltage is obtained is the moment when the voltage is equal to or above the nominal voltage (VI > V2) and at this moment operation of the DC/DC converter is stopped.
9. A voltage booster for engine generator as claimed in Claim 1, wherein the active boosting circuit is a DC/DC converter having:
voltage V2 (VI > V2) and at this moment the relay is
a feedback circuit for performing feedback so that the voltage of the output side becomes the
predetermined nominal voltage V2,
said condenser is inserted between said feedback circuit and said output side, and
a bypass circuit bypassing from the input side to the output side of the active boosting circuit by a predetermined voltage drop, and
a control circuit for terminating operation of the active boosting circuit by the output of the feedback circuit,
and at the moment when the voltage VI of the input side bypassed to the output side has become a predetermined voltage from the voltage adjusting device during the stationary operation, the feedback circuit stops the boosting operation of the DC/DC converter.
10. A voltage booster for engine generator as claimed in Claim 9, wherein the predetermined moment is the moment when the voltage has exceeded the nominal voltage V2 and at this moment boosting operation of the DC/DC converter is stopped.
11. . - *¦ An ignition control method for an engine ignition apparatus of the full transistor igniter method having a battery and a generator which can be driven by the kick method, the method comprising steps of:
boosting voltage driven by a kick to a predetermined nominal voltage of the stationary
operation of the ignition apparatus by sequential charging while a low voltage of a generator insufficient for engine stationary operation is output and applying the boosted voltage to the ignition apparatus, and
terminating the boosting operation when the voltage has become equal to or above the voltage of stationary operation and applying the output voltage of the generator directly to the ignition apparatus.

A voltage booster for engine generator comprising an engine ignition apparatus of the full transistor igniter method capable of igniting the engine by the kick method. Between a voltage adjusting device receiving a start current from the kick-driven generator and an electronic device such as an ECU connected to the voltage adjusting device, there is connected in parallel an active boosting circuit performing boosting operation only during output of a low voltage of the voltage adjusting device upon engine start by kick and terminating the boosting operation when the stationary operation is set in after the engine start. A control method of the voltage booster is also disclosed.

A VOLTAGE BOOSTER FOR ENGINE GENERATOR AND A METHOD FOR CONTROL OF THE VOLTAGE BOOSTER

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