US20080291599A1 - Ignition device and method of controlling the same - Google Patents
Ignition device and method of controlling the same Download PDFInfo
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- US20080291599A1 US20080291599A1 US12/071,216 US7121608A US2008291599A1 US 20080291599 A1 US20080291599 A1 US 20080291599A1 US 7121608 A US7121608 A US 7121608A US 2008291599 A1 US2008291599 A1 US 2008291599A1
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- Prior art keywords
- gate
- voltage
- switching element
- semiconductor switching
- constant
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P3/00—Other installations
- F02P3/02—Other installations having inductive energy storage, e.g. arrangements of induction coils
- F02P3/04—Layout of circuits
- F02P3/05—Layout of circuits for control of the magnitude of the current in the ignition coil
- F02P3/051—Opening or closing the primary coil circuit with semiconductor devices
- F02P3/053—Opening or closing the primary coil circuit with semiconductor devices using digital techniques
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P3/00—Other installations
- F02P3/02—Other installations having inductive energy storage, e.g. arrangements of induction coils
- F02P3/04—Layout of circuits
- F02P3/0407—Opening or closing the primary coil circuit with electronic switching means
- F02P3/0435—Opening or closing the primary coil circuit with electronic switching means with semiconductor devices
- F02P3/0442—Opening or closing the primary coil circuit with electronic switching means with semiconductor devices using digital techniques
Definitions
- the present invention relates to an ignition device for controlling an ignition with a plug and/or relates to a method of controlling the ignition device.
- an ignition device controls an electric current to be applied to a primary winding of an ignition coil for controlling an ignition of an engine by using a plug.
- the plug is coupled with a secondary winding of the ignition coil.
- a positive voltage i.e., an on-voltage
- a spark may be generated at the plug and an early ignition may occur.
- a voltage generated at the ignition coil tends to increase, and thereby the on-voltage also increases. Thus, a requirement for reducing the on-voltage further increases.
- An ignition device 101 in FIG. 6 includes an insulated gate bipolar transistor (IGBT) 100 , a first resistor 102 and a second resistor 103 disposed between a power source 109 and the IGBT 100 , an NPN transistor 104 coupled between the first resistor 102 and the second resistor 103 , and a waveform-shaping circuit 106 coupled with the NPN transistor 104 and an engine electronic control unit (engine ECU) 105 .
- the waveform-shaping circuit 106 is disposed to shape a waveform of an ignition signal from the engine ECU 105 .
- the NPN transistor 104 is switched in accordance with the waveform-shaped signal, thereby controlling an electric current to be supplied to a gate of the IGBT 100 .
- the on-voltage generated at the plug can be reduced by increasing a resistance value of the first resistor 102 .
- the resistance value of the first resistor 102 is selected so that the on-voltage reduces and the initial energization time is secured. Therefore, a selection of the first resistor 102 is limited.
- a battery voltage may be reduced in accordance with a running condition or an operating condition of the electric devices. For example, the battery voltage reduces easily when the vehicle starts to run. When the battery voltage reduces, the increasing rate of the gate voltage reduces and the initial energization time fluctuates. Thus, the coil current for keeping a predetermined ignition performance may not flow in the ignition coil 108 . This problem may be solved by reducing the resistance value of the first resistor 102 . However, if the resistance value of the first resistor 102 reduces, the on-voltage reversely increases when the battery voltage is high. As a result, considering a case where the battery voltage reduces, it is difficult to reduce the on-voltage while securing a necessary initial energization time for the ignition.
- an ignition device includes a semiconductor switching element, a constant-current circuit, and a control section.
- the semiconductor switching element has a metal-oxide semiconductor structure having a gate, a collector, and an emitter, and is coupled with a primary winding of an ignition coil.
- the semiconductor switching element is configured to control a gate voltage and an electric current flowing between the collector and the emitter so as to control a coil current flowing in the primary winding, a voltage at two ends of a secondary winding of the ignition coil, and an electric discharge at a plug coupled with the secondary winding.
- the constant-current circuit is coupled with the gate of the semiconductor switching element to supply a constant current to the gate, so that an electric charge is accumulated at the gate and the gate voltage increases.
- the control section is configured to switch the semiconductor switching element by switching a supply or non-supply of the constant current generated at the constant-current circuit to the gate of the semiconductor switching element based on an ignition signal.
- a method of controlling an ignition device includes: generating a constant current at a constant-current circuit; supplying the constant current to a gate of a semiconductor switching element in accordance with an ignition signal; and controlling a gate voltage of the semiconductor switching element and an electric current flowing between a collector and an emitter of the semiconductor switching element so as to control a coil current flowing in a primary winding of an ignition coil, a voltage at two ends of a secondary winding of the ignition coil, and an electric discharge at a plug coupled with the secondary winding.
- FIG. 1 is a schematic diagram showing an ignition system including an ignition device according to an embodiment of the invention
- FIG. 2 is a timing chart for controlling components of the ignition device according to the embodiment
- FIG. 3 is an enlarged timing chart of a gate voltage of an IGBT during a time TA shown in FIG. 2 ;
- FIG. 4 is a timing chart for controlling components of an ignition device according to a related art
- FIGS. 5A-5C are enlarged timing charts of a gate voltage of an IGBT during a time TA shown in FIG. 4 , in a case where a voltage of a power source is at a normal level, a high level, and a low level, respectively;
- FIG. 6 is a schematic diagram showing an ignition system including the ignition device according to the related art.
- An ignition device 1 can be suitably used for an internal combustion engine.
- the ignition device 1 includes a waveform-shaping circuit 2 , an NPN transistor 3 , a resistor 4 , an insulated gate bipolar transistor (IGBT) 5 , and a constant-current circuit 6 .
- the ignition device 1 is configured to control an electricity supply from a power source 9 (e.g., battery) to a primary winding Ba of an ignition coil 8 based on an ignition signal from an engine electronic control unit (engine ECU) 7 .
- a power source 9 e.g., battery
- the waveform of ignition signal from the engine ECU 7 is shaped at the waveform-shaping circuit 2 .
- the NPN transistor 3 is controlled by changing a gate voltage of the NPN transistor 3 based on the waveform-shaped signal. For example, the engine ECU 7 outputs an ignition signal at a low level before the ignition coil 8 is supplied with electricity, and outputs an ignition signal at a high level when the ignition coil 8 is supplied with electricity. A level of the ignition signal is reversed at the waveform-shaping circuit 2 , and the NPN transistor 3 is switched by the reversed ignition signal.
- a collector of the NPN transistor 3 is coupled with a gate of the IGBT 5 through the resistor 4 for protecting an input, and a gate voltage VG applied to the gate of the IGBT 5 is controlled in accordance with an on/off state of the NPN transistor 3 .
- a collector voltage of the NPN transistor 3 i.e., the gate voltage VG of the IGBT 5
- the gate voltage VG of the IGBT 5 is high.
- the IGBT 5 is turned on.
- the primary winding 8 a of the ignition coil 8 which is coupled with the IGBT 5 , is not supplied with electricity. In this case, because a potential difference is not generated between two ends of the primary winding 8 a, a potential difference is not generated between two ends of a secondary winding 8 b, either. In contrast, when the IGBT 5 is on, the primary winding 8 a is supplied with electricity from the power source 9 (e.g., a buttery), and thereby a potential difference is provided between the two ends of the primary winding 8 a.
- the power source 9 e.g., a buttery
- a potential difference which is higher than the potential difference at the primary winding 8 a by a ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, is generated between the two ends of the secondary winding 8 b, and thereby an on-voltage is generated at an electrode of a plug 10 .
- a collector voltage VC of the IGBT 5 increases, and the potential difference is generated at the two ends of the primary winding 8 a.
- the potential difference which is higher than the potential difference at the primary winding 8 a by a ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, is generated between the two ends of the secondary winding 8 b, and thereby the plug 10 , which is coupled with the secondary winding 8 b, discharges electricity.
- the ignition device 1 can control an ignition time of the plug 10 based on the ignition signal from the engine ECU 7 .
- the constant-current circuit 6 is disposed at a channel between the power source 9 and the gate of the IGBT 5 .
- the transistor 3 When the transistor 3 is off, an electric charge is accumulated at the gate of the IGBT 5 in accordance with a constant-current generated at the constant-current circuit 6 .
- the gate voltage VG applied to the gate of the IGBT 5 increases and the IGBT 5 is turned on.
- a current value of the constant-current circuit 6 may be about in a range from 10 ⁇ A to 200 ⁇ A.
- the ignition signal transitions from the low level to the high level at the time T 1 shown in FIG. 2 , the ignition signal is reversed into the low level at the waveform-shaping circuit 2 , and thereby the NPN transistor 3 is turned off.
- the electric charge is accumulated at the gate of the IGBT 5 through the resistor 4 in accordance with the constant current generated at the constant-current circuit 6 . Because an accumulating rate is limited by the constant current, the electric charge is accumulated at the gate of the IGBT 5 at a constant rate.
- the gate of the IGBT 5 has an input capacitance, and thereby an increasing rate of the gate voltage VG can be reduced until a predetermined electric charge is accumulated.
- the increasing rate of the gate voltage VG can be reduced.
- the gate voltage VG increases to a threshold voltage Vt of the IGBT 5 approximately linearly and relatively slowly by a gradient of ⁇ 1 , as shown in FIG. 3 .
- the IGBT 5 When the predetermined electric charge is accumulated in the IGBT 5 and the gate voltage VG reaches the threshold voltage Vt at the time T 2 shown in FIGS. 2 and 3 , the IGBT 5 is switched from off to on. Thereby, the corrector voltage VC of the IGBT 5 reduces, a potential difference is generated between the two ends of the primary winding 8 a, and the electricity is supplied to the primary winding 8 a. As a result, the two ends of the secondary winding 8 b have a high voltage in accordance with the ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, and thereby the on-voltage is generated by the voltage V 2 at the plug 10 .
- the coil current starts to flow.
- a current-carrying capacity of the IGBT 5 that is, an electric current flowing between a collector and an emitter of the IGBT 5 is limited.
- the corrector voltage VC of the IGBT 5 starts to reduce slowly from the voltage VB of the power source 9 .
- the corrector voltage VC reduces, the electric current supplied to the gate of the IGBT 5 is accumulated in accordance with a capacity between the corrector and the gate and a change in the corrector voltage VC.
- the gate voltage VG is maintained at the threshold voltage Vt.
- a maintaining time where the gate voltage VG is maintained at the threshold voltage Vt i.e., a time between T 2 and T 3 shown in FIGS. 2 and 3 , is determined in accordance with the constant current generated at the constant-current circuit 6 .
- the constant current is about in the range from 10 ⁇ A to 200 ⁇ A
- the maintaining time is about in a range from 5 ⁇ sec to 200 ⁇ sec.
- the corrector voltage VC reduces toward the minimum, the predetermined electric charge is accumulated at the gate of the IGBT 5 .
- the current-carrying capacity of the IGBT 5 i.e., the electricity supply to the primary winding 8 a is no longer limited, and the gate voltage VG increases approximately linearly by the gradient of ⁇ 1 again.
- the predetermined electric current is supplied to the primary winding 8 a, and the IGBT 5 is turned off, the corrector voltage VC of the IGBT 5 increases and the potential difference is generated between the two ends of the primary winding 8 a.
- the potential difference which is higher than the potential difference at the primary winding 8 a by the ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, is generated between the two ends of the secondary winding 8 b.
- the plug 10 coupled with the secondary winding 8 b discharges electricity for an ignition.
- the ignition device 1 because the electric charge is accumulated at the gate of the IGBT 5 in accordance with the constant current generated at the constant-current circuit 6 , the accumulating rate is maintained at a constant level. Thus, the increasing rate of the gate voltage VG can be reduced.
- An initial energization time ⁇ t 0 at which the current-carrying capacity of the IGBT 5 is limited after the gate voltage VG reaches the threshold voltage Vt and the coil current starts to flow is determined based on the maintaining time where the gate voltage VG is maintained at the threshold voltage Vt. Furthermore, the maintaining time can be determined in accordance with the constant-current generated at the constant-current circuit 6 .
- the initial energization time ⁇ t 0 can be controlled, and a decreasing rate of the corrector voltage VC also can be controlled.
- the initial energization time ⁇ t 0 is long and the decreasing rate of the corrector voltage VC of the IGBT 5 is reduced, the voltage applied to the two ends of the secondary winding 8 b can be reduced, and thereby the on-voltage of the voltage V 2 at the plug 10 also can be reduced.
- the gate voltage VG changes in a manner similar to a case where the voltage VB is at a normal level, as shown by the dotted line in FIG. 3 , and the initial energization time ⁇ t 0 is substantially constant regardless the voltage VB.
- an electric charge is accumulated at a gate of an IGBT 100 through resistors 102 and 103 . Because electricity is supplied to the gate of the IGBT 100 through the resistors 102 and 103 , when a gate voltage VG increases to a threshold voltage Vt and when the gate voltage VG increases from the threshold voltage Vt, the gate voltage VG further increases along an exponential curve in accordance with a time constant of a charging circuit formed by a capacitor (i.e., a gate capacity) and the resistors 102 and 103 , as shown in FIGS. 5A-5C .
- a capacitor i.e., a gate capacity
- a gradient ⁇ 2 of the exponential curve is larger than the gradient ⁇ 1 shown in FIGS. 2 and 3 , and the maintaining time where the gate voltage VG is maintained at the threshold voltage Vt is shorter than that of the ignition device 1 according to the embodiment.
- an increasing rate of the gate voltage VG and a decreasing rate of a corrector voltage VC of the ignition device 101 are greater than those of the ignition device 1 , as shown in FIGS. 2 and 4 .
- a voltage V 2 at two ends of a secondary winding 108 b of an ignition coil 108 is higher than necessary, and thereby an on-voltage of a plug 110 increases in the ignition device 101 .
- the ignition device 1 because electric charge is accumulated at the gate of the IGBT 5 in accordance with the constant current generated at the constant-current circuit 6 , the on-voltage can be reduced by a voltage ⁇ v 0 compared with the related art, and the initial energization time ⁇ t 0 can be secured, as shown in FIGS. 2 and 4 . Additionally, because the constant-current circuit 6 is provided instead of a resistor having a high resistance value, a range of selection increases.
- the initial energization time ⁇ t 0 can have a substantially constant length.
- the ignition device 1 is less affected by the reduction of the battery voltage.
- a flying spark at a time where the on-voltage is generated at the plug 10 can be restricted with a high degree of certainty.
- the ignition device 1 is not required to have the diode.
- the IGBT 5 is provided as a semiconductor switching element for a low-load driving, as an example.
- a power metal-oxide semiconductor field-effect transistor MOSFET may be used as the semiconductor switching element, for example.
- the waveform-shaping circuit 2 and the NPN transistor 3 function as a control section that controls the supply of the constant current generated at the constant-current circuit 6 to the gate of the IGBT 5 , as an example.
- other circuit structure may be used.
- MOS metal-oxide semiconductor
Abstract
An ignition device includes a semiconductor switching element, a constant-current circuit, and a control section. The semiconductor switching element has a gate, a collector and an emitter, and is coupled with a primary winding of an ignition coil. The semiconductor switching element is configured to control a gate voltage and an electric current flowing between the collector and the emitter so as to control a coil current flowing in the primary winding, a voltage at two ends of a secondary winding, and an electric discharge at a plug coupled with the secondary winding. The constant-current circuit is coupled with the gate for supplying a constant current to the gate. The control section is configured to switch the semiconductor switching element by switching a supply or non-supply of the constant current to the gate based on an ignition signal.
Description
- This application is based on Japanese Patent Application No. 2007-137775 filed on May 24, 2007, the contents of which are incorporated herein by reference in its entirety.
- 1. Field of the Invention
- The present invention relates to an ignition device for controlling an ignition with a plug and/or relates to a method of controlling the ignition device.
- 2. Description of the Related Art
- Conventionally, an ignition device controls an electric current to be applied to a primary winding of an ignition coil for controlling an ignition of an engine by using a plug. The plug is coupled with a secondary winding of the ignition coil. When an electricity supply to the ignition coil is started, a positive voltage (i.e., an on-voltage) is generated at the plug. In this case, a spark may be generated at the plug and an early ignition may occur. Additionally, when an engine is in high compression and lean-burn, a voltage generated at the ignition coil tends to increase, and thereby the on-voltage also increases. Thus, a requirement for reducing the on-voltage further increases.
- An
ignition device 101 inFIG. 6 includes an insulated gate bipolar transistor (IGBT) 100, afirst resistor 102 and asecond resistor 103 disposed between apower source 109 and theIGBT 100, anNPN transistor 104 coupled between thefirst resistor 102 and thesecond resistor 103, and a waveform-shaping circuit 106 coupled with theNPN transistor 104 and an engine electronic control unit (engine ECU) 105. The waveform-shaping circuit 106 is disposed to shape a waveform of an ignition signal from theengine ECU 105. TheNPN transistor 104 is switched in accordance with the waveform-shaped signal, thereby controlling an electric current to be supplied to a gate of theIGBT 100. In theignition device 101, the on-voltage generated at the plug can be reduced by increasing a resistance value of thefirst resistor 102. - However, when the resistance value of the
first resistor 102 is too high, an increasing rate of a gate voltage reduces, and a time for which the gate voltage reaches a threshold voltage becomes longer. When the gate voltage reaches the threshold voltage, a coil current starts to flow. Thus, an initial energization time from the start of the coil current flow to anignition coil 108 becomes shorter. As a result, depending on an operating condition, for example, at a high engine rotation speed, the initial energization time may be shorter than a predetermined time and a predetermined voltage may be not generated at theignition coil 108, and thereby a misfire may be caused. Thus, the resistance value of thefirst resistor 102 is selected so that the on-voltage reduces and the initial energization time is secured. Therefore, a selection of thefirst resistor 102 is limited. - Additionally, when electric devices mounted on a vehicle increases, an electric load to a vehicle battery increases. Thus, a battery voltage may be reduced in accordance with a running condition or an operating condition of the electric devices. For example, the battery voltage reduces easily when the vehicle starts to run. When the battery voltage reduces, the increasing rate of the gate voltage reduces and the initial energization time fluctuates. Thus, the coil current for keeping a predetermined ignition performance may not flow in the
ignition coil 108. This problem may be solved by reducing the resistance value of thefirst resistor 102. However, if the resistance value of thefirst resistor 102 reduces, the on-voltage reversely increases when the battery voltage is high. As a result, considering a case where the battery voltage reduces, it is difficult to reduce the on-voltage while securing a necessary initial energization time for the ignition. - It is an object of the present invention to provide an ignition device and/or a method of controlling the ignition device. Specifically, the ignition device can reduce an on-voltage while securing an initial energization time.
- According to an aspect of the invention, an ignition device includes a semiconductor switching element, a constant-current circuit, and a control section. The semiconductor switching element has a metal-oxide semiconductor structure having a gate, a collector, and an emitter, and is coupled with a primary winding of an ignition coil. The semiconductor switching element is configured to control a gate voltage and an electric current flowing between the collector and the emitter so as to control a coil current flowing in the primary winding, a voltage at two ends of a secondary winding of the ignition coil, and an electric discharge at a plug coupled with the secondary winding. The constant-current circuit is coupled with the gate of the semiconductor switching element to supply a constant current to the gate, so that an electric charge is accumulated at the gate and the gate voltage increases. The control section is configured to switch the semiconductor switching element by switching a supply or non-supply of the constant current generated at the constant-current circuit to the gate of the semiconductor switching element based on an ignition signal.
- According to another aspect of the invention, a method of controlling an ignition device includes: generating a constant current at a constant-current circuit; supplying the constant current to a gate of a semiconductor switching element in accordance with an ignition signal; and controlling a gate voltage of the semiconductor switching element and an electric current flowing between a collector and an emitter of the semiconductor switching element so as to control a coil current flowing in a primary winding of an ignition coil, a voltage at two ends of a secondary winding of the ignition coil, and an electric discharge at a plug coupled with the secondary winding.
- In the above-described ignition device and the method of controlling the ignition device, because the electric charge is accumulated at the gate of the semiconductor switching element in accordance with the constant current generated at the constant-current circuit, an accumulating rate is maintained at a constant level, and thereby an increasing rate of the gate voltage can be reduced. Accordingly, an initial energization time can be secured, and the on-voltage of the plug can be reduced.
- Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiment when taken together with the accompanying drawings. In the drawings:
-
FIG. 1 is a schematic diagram showing an ignition system including an ignition device according to an embodiment of the invention; -
FIG. 2 is a timing chart for controlling components of the ignition device according to the embodiment; -
FIG. 3 is an enlarged timing chart of a gate voltage of an IGBT during a time TA shown inFIG. 2 ; -
FIG. 4 is a timing chart for controlling components of an ignition device according to a related art; -
FIGS. 5A-5C are enlarged timing charts of a gate voltage of an IGBT during a time TA shown inFIG. 4 , in a case where a voltage of a power source is at a normal level, a high level, and a low level, respectively; and -
FIG. 6 is a schematic diagram showing an ignition system including the ignition device according to the related art. - An
ignition device 1 according to an embodiment of the invention can be suitably used for an internal combustion engine. As shown inFIG. 1 , theignition device 1 includes a waveform-shaping circuit 2, anNPN transistor 3, aresistor 4, an insulated gate bipolar transistor (IGBT) 5, and a constant-current circuit 6. Theignition device 1 is configured to control an electricity supply from a power source 9 (e.g., battery) to a primary winding Ba of anignition coil 8 based on an ignition signal from an engine electronic control unit (engine ECU) 7. - The waveform of ignition signal from the engine ECU 7 is shaped at the waveform-shaping
circuit 2. TheNPN transistor 3 is controlled by changing a gate voltage of theNPN transistor 3 based on the waveform-shaped signal. For example, the engine ECU 7 outputs an ignition signal at a low level before theignition coil 8 is supplied with electricity, and outputs an ignition signal at a high level when theignition coil 8 is supplied with electricity. A level of the ignition signal is reversed at the waveform-shapingcircuit 2, and theNPN transistor 3 is switched by the reversed ignition signal. - A collector of the
NPN transistor 3 is coupled with a gate of theIGBT 5 through theresistor 4 for protecting an input, and a gate voltage VG applied to the gate of theIGBT 5 is controlled in accordance with an on/off state of theNPN transistor 3. Specifically, when theNPN transistor 3 is on, a collector voltage of the NPN transistor 3 (i.e., the gate voltage VG of the IGBT 5) is about zero. Thus, the IGBT 5 is turned off. In contrast, when theNPN transistor 3 is off, the gate voltage VG of theIGBT 5 is high. Thus, theIGBT 5 is turned on. - When the
IGBT 5 is off, the primary winding 8a of theignition coil 8, which is coupled with theIGBT 5, is not supplied with electricity. In this case, because a potential difference is not generated between two ends of the primary winding 8 a, a potential difference is not generated between two ends of a secondary winding 8 b, either. In contrast, when theIGBT 5 is on, the primary winding 8 a is supplied with electricity from the power source 9 (e.g., a buttery), and thereby a potential difference is provided between the two ends of the primary winding 8 a. Thus, a potential difference, which is higher than the potential difference at the primary winding 8 a by a ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, is generated between the two ends of the secondary winding 8 b, and thereby an on-voltage is generated at an electrode of aplug 10. When theIGBT 5 is turned off after a predetermined electric current is supplied to the primary winding 8 a, a collector voltage VC of theIGBT 5 increases, and the potential difference is generated at the two ends of the primary winding 8 a. Thus, the potential difference, which is higher than the potential difference at the primary winding 8 a by a ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, is generated between the two ends of the secondary winding 8 b, and thereby theplug 10, which is coupled with the secondary winding 8 b, discharges electricity. As a result, theignition device 1 can control an ignition time of theplug 10 based on the ignition signal from theengine ECU 7. - In the
ignition device 1, the constant-current circuit 6 is disposed at a channel between thepower source 9 and the gate of theIGBT 5. When thetransistor 3 is off, an electric charge is accumulated at the gate of theIGBT 5 in accordance with a constant-current generated at the constant-current circuit 6. Thereby, the gate voltage VG applied to the gate of theIGBT 5 increases and theIGBT 5 is turned on. For example, a current value of the constant-current circuit 6 may be about in a range from 10 μA to 200 μA. - An operation of the
ignition device 1 will now be described with reference toFIGS. 2 and 3 . When the ignition signal from theengine ECU 7 is at the low level, the ignition signal is reversed into the high level at the waveform-shaping circuit 2, and thereby theNPN transistor 3 is turned on. Thus, a potential difference between the collector and an emitter of theNPN transistor 3 is about zero, and the constant current generated at the constantcurrent circuit 6 flows to theNPN transistor 3. As a result, theIGBT 5 is turned off. - When the ignition signal transitions from the low level to the high level at the time T1 shown in
FIG. 2 , the ignition signal is reversed into the low level at the waveform-shaping circuit 2, and thereby theNPN transistor 3 is turned off. Thus, the electric charge is accumulated at the gate of theIGBT 5 through theresistor 4 in accordance with the constant current generated at the constant-current circuit 6. Because an accumulating rate is limited by the constant current, the electric charge is accumulated at the gate of theIGBT 5 at a constant rate. The gate of theIGBT 5 has an input capacitance, and thereby an increasing rate of the gate voltage VG can be reduced until a predetermined electric charge is accumulated. Thus, when a time for accumulating the electric charge of the input capacitance of the gate of theIGBT 5 is long, the increasing rate of the gate voltage VG can be reduced. As a result, the gate voltage VG increases to a threshold voltage Vt of theIGBT 5 approximately linearly and relatively slowly by a gradient of θ1, as shown inFIG. 3 . - When the predetermined electric charge is accumulated in the
IGBT 5 and the gate voltage VG reaches the threshold voltage Vt at the time T2 shown inFIGS. 2 and 3 , theIGBT 5 is switched from off to on. Thereby, the corrector voltage VC of theIGBT 5 reduces, a potential difference is generated between the two ends of the primary winding 8 a, and the electricity is supplied to the primary winding 8 a. As a result, the two ends of the secondary winding 8 b have a high voltage in accordance with the ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, and thereby the on-voltage is generated by the voltage V2 at theplug 10. - When the gate voltage VG reaches the threshold voltage Vt, the coil current starts to flow. However, when the gate voltage VG is near the threshold voltage Vt, a current-carrying capacity of the
IGBT 5, that is, an electric current flowing between a collector and an emitter of theIGBT 5 is limited. Thus, the corrector voltage VC of theIGBT 5 starts to reduce slowly from the voltage VB of thepower source 9. When the corrector voltage VC reduces, the electric current supplied to the gate of theIGBT 5 is accumulated in accordance with a capacity between the corrector and the gate and a change in the corrector voltage VC. Thus, the gate voltage VG is maintained at the threshold voltage Vt. A maintaining time where the gate voltage VG is maintained at the threshold voltage Vt, i.e., a time between T2 and T3 shown inFIGS. 2 and 3 , is determined in accordance with the constant current generated at the constant-current circuit 6. For example, when the constant current is about in the range from 10 μA to 200 μA, the maintaining time is about in a range from 5 μsec to 200 μsec. - When the corrector voltage VC reduces toward the minimum, the predetermined electric charge is accumulated at the gate of the
IGBT 5. Thus, the current-carrying capacity of theIGBT 5, i.e., the electricity supply to the primary winding 8 a is no longer limited, and the gate voltage VG increases approximately linearly by the gradient of θ1 again. When the predetermined electric current is supplied to the primary winding 8 a, and theIGBT 5 is turned off, the corrector voltage VC of theIGBT 5 increases and the potential difference is generated between the two ends of the primary winding 8 a. Thereby, the potential difference, which is higher than the potential difference at the primary winding 8 a by the ratio of the number of windings of the secondary winding 8 b to the number of windings of the primary winding 8 a, is generated between the two ends of the secondary winding 8 b. As a result, theplug 10 coupled with the secondary winding 8 b discharges electricity for an ignition. - In the
ignition device 1, because the electric charge is accumulated at the gate of theIGBT 5 in accordance with the constant current generated at the constant-current circuit 6, the accumulating rate is maintained at a constant level. Thus, the increasing rate of the gate voltage VG can be reduced. An initial energization time Δt0 at which the current-carrying capacity of theIGBT 5 is limited after the gate voltage VG reaches the threshold voltage Vt and the coil current starts to flow is determined based on the maintaining time where the gate voltage VG is maintained at the threshold voltage Vt. Furthermore, the maintaining time can be determined in accordance with the constant-current generated at the constant-current circuit 6. As a result, the initial energization time Δt0 can be controlled, and a decreasing rate of the corrector voltage VC also can be controlled. When the initial energization time Δt0 is long and the decreasing rate of the corrector voltage VC of theIGBT 5 is reduced, the voltage applied to the two ends of the secondary winding 8 b can be reduced, and thereby the on-voltage of the voltage V2 at theplug 10 also can be reduced. - Even when the voltage VB of the
power source 9 is changed to increase or decrease, the gate voltage VG changes in a manner similar to a case where the voltage VB is at a normal level, as shown by the dotted line inFIG. 3 , and the initial energization time Δt0 is substantially constant regardless the voltage VB. Thus, the even when the voltage VB of thepower source 9 changes, the on-voltage can be reduced. - In an
ignition device 101 according a related art shown inFIG. 6 , when the ignition signal transitions from the low level to the high level at the time T1 shown inFIG. 4 , an electric charge is accumulated at a gate of anIGBT 100 throughresistors IGBT 100 through theresistors resistors FIGS. 5A-5C . Additionally, a gradient θ2 of the exponential curve is larger than the gradient θ1 shown inFIGS. 2 and 3 , and the maintaining time where the gate voltage VG is maintained at the threshold voltage Vt is shorter than that of theignition device 1 according to the embodiment. Thus, an increasing rate of the gate voltage VG and a decreasing rate of a corrector voltage VC of theignition device 101 are greater than those of theignition device 1, as shown inFIGS. 2 and 4 . As a result, a voltage V2 at two ends of a secondary winding 108 b of anignition coil 108 is higher than necessary, and thereby an on-voltage of aplug 110 increases in theignition device 101. - Even in the
ignition device 101, when apower source 109 is at the normal level (e.g., a battery voltage is about 12 V) and the maintaining time is controlled by changing a resistance value of theresistor 102 or a thickness of a gate insulating layer, a changing time of the corrector voltage VC can be controlled in a manner similar to that of theignition device 1. Thus, a voltage at two ends of a primary winding 108 a of theignition coil 108 can be reduced, and thereby the on-voltage, which is determined in accordance with the voltage at the two ends of the secondary winding 108 b, also can be reduced. - However, when the voltage of the
power source 109 is higher than the normal level, the increasing rate of the gate voltage VG increases and the gradient θ2 increases, as shown inFIG. 5B . In contrast, when the voltage of thepower source 109 is lower than the normal level, the increasing rate of the gate voltage VG decreases and the gradient θ2 decreases, as shown inFIG. 5C . Thus, the initial energization time Δt0 changes in accordance with the voltage of thepower source 109. As a result, when the voltage of thepower source 109 reduces, theignition coil 108 may not be supplied with electricity. - In the
ignition device 1 according to the embodiment of the present invention, because electric charge is accumulated at the gate of theIGBT 5 in accordance with the constant current generated at the constant-current circuit 6, the on-voltage can be reduced by a voltage Δv0 compared with the related art, and the initial energization time Δt0 can be secured, as shown inFIGS. 2 and 4 . Additionally, because the constant-current circuit 6 is provided instead of a resistor having a high resistance value, a range of selection increases. - Furthermore, because the constant-
current circuit 6 is used, even when the voltage VB of thepower source 9 fluctuates, the initial energization time Δt0 can have a substantially constant length. Thus, even when the voltage VB of thepower source 9 reduces, for example, when the battery voltage reduces, theignition device 1 is less affected by the reduction of the battery voltage. - When a diode is disposed between the primary winding 8 a and the secondary winding 8 b of the
ignition coil 8, a flying spark at a time where the on-voltage is generated at theplug 10 can be restricted with a high degree of certainty. However, because the on-voltage can be reduced in theignition device 1, theignition device 1 is not required to have the diode. - Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.
- In the above-described embodiment, the
IGBT 5 is provided as a semiconductor switching element for a low-load driving, as an example. Alternatively, a power metal-oxide semiconductor field-effect transistor (MOSFET) may be used as the semiconductor switching element, for example. - In the above-described embodiment, the waveform-
shaping circuit 2 and theNPN transistor 3 function as a control section that controls the supply of the constant current generated at the constant-current circuit 6 to the gate of theIGBT 5, as an example. Alternatively, other circuit structure may be used. For example, a metal-oxide semiconductor (MOS) transistor may be used instead of theNPN transistor 3. - Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.
Claims (8)
1. An ignition device for controlling an ignition with a plug coupled with an ignition coil that includes a primary winding and a secondary winding, the ignition device comprising:
a semiconductor switching element that has a metal-oxide semiconductor structure having a gate, a collector and an emitter, and that is coupled with the primary winding, the semiconductor switching element being configured to control a gate voltage and an electric current flowing between the collector and the emitter so as to control a coil current flowing in the primary winding, a voltage at two ends of the secondary winding, and an electric discharge at the plug;
a constant-current circuit coupled with the gate of the semiconductor switching element for supplying a constant current to the gate, so that an electric charge is accumulated at the gate and the gate voltage increases; and
a control section configured to switch the semiconductor switching element by switching a supply or non-supply of the constant current generated at the constant-current circuit to the gate of the semiconductor switching element based on an ignition signal.
2. The ignition device according to claim 1 , wherein:
the gate voltage of the semiconductor switching element increases approximately linearly to a threshold voltage of the semiconductor switching element by a predetermined gradient, then is maintained at the threshold voltage for a predetermined time, and further increases from the threshold voltage approximately linearly by the predetermined gradient, when the constant current is supplied to the gate.
3. The ignition device according to claim 2 , wherein:
the predetermined time is about in a range from 5 μs to 200 μs.
4. The ignition device according to claim 1 , wherein:
the constant current has a current value about in a range from 10 μA to 200 μA.
5. A method of controlling an ignition device that includes a semiconductor switching element and a constant-current circuit, the method comprising:
generating a constant current at the constant-current circuit;
supplying the constant current to a gate of the semiconductor switching element in accordance with an ignition signal; and
controlling a gate voltage of the semiconductor switching element and an electric current flowing between a collector and an emitter of the semiconductor switching element so as to control a coil current flowing in a primary winding of an ignition coil, a voltage at two ends of a secondary winding of the ignition coil, and an electric discharge at a plug coupled with the secondary winding.
6. The method according to claim 5 , wherein:
the gate voltage of the semiconductor switching element increases approximately linearly to a threshold voltage of the semiconductor switching element by a predetermined gradient, then is maintained at the threshold voltage for a predetermined time, and further increases from the threshold voltage approximately linearly by the predetermined gradient, when the constant current is supplied to the gate.
7. The method according to claim 6 , wherein:
the predetermined time is about in a range from 5 μs to 200 μs.
8. The method according to claim 5 , wherein:
the constant current has a current value about in a range from 10 μA to 200 μA.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007-137775 | 2007-05-24 | ||
JP2007137775A JP2008291728A (en) | 2007-05-24 | 2007-05-24 | Igniter for internal combustion engine |
Publications (1)
Publication Number | Publication Date |
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US20080291599A1 true US20080291599A1 (en) | 2008-11-27 |
Family
ID=40072172
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/071,216 Abandoned US20080291599A1 (en) | 2007-05-24 | 2008-02-19 | Ignition device and method of controlling the same |
Country Status (2)
Country | Link |
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US (1) | US20080291599A1 (en) |
JP (1) | JP2008291728A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104682203A (en) * | 2015-03-13 | 2015-06-03 | 温州大学城市学院 | Ignition circuit of separately-excited arc lighter |
US9401705B2 (en) | 2011-07-07 | 2016-07-26 | Fuji Electric Co., Ltd. | Gate driving device |
CN107084405A (en) * | 2017-04-09 | 2017-08-22 | 王红 | Igniter used in a kind of medium-high frequency sintering firing equipment |
CN108700015A (en) * | 2016-02-17 | 2018-10-23 | 株式会社电装 | Igniter |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4495931A (en) * | 1982-08-05 | 1985-01-29 | Robert Bosch Gmbh | Engine ignition system |
US7293931B2 (en) * | 2004-05-13 | 2007-11-13 | Bao Sheng Corporation | Enhanced fluid dispenser container fitment |
US20080012041A1 (en) * | 2006-07-11 | 2008-01-17 | Kesler Scott B | Switching control system to reduce coil output voltage when commencing coil charging |
-
2007
- 2007-05-24 JP JP2007137775A patent/JP2008291728A/en not_active Withdrawn
-
2008
- 2008-02-19 US US12/071,216 patent/US20080291599A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4495931A (en) * | 1982-08-05 | 1985-01-29 | Robert Bosch Gmbh | Engine ignition system |
US7293931B2 (en) * | 2004-05-13 | 2007-11-13 | Bao Sheng Corporation | Enhanced fluid dispenser container fitment |
US20080012041A1 (en) * | 2006-07-11 | 2008-01-17 | Kesler Scott B | Switching control system to reduce coil output voltage when commencing coil charging |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9401705B2 (en) | 2011-07-07 | 2016-07-26 | Fuji Electric Co., Ltd. | Gate driving device |
CN104682203A (en) * | 2015-03-13 | 2015-06-03 | 温州大学城市学院 | Ignition circuit of separately-excited arc lighter |
CN108700015A (en) * | 2016-02-17 | 2018-10-23 | 株式会社电装 | Igniter |
CN107084405A (en) * | 2017-04-09 | 2017-08-22 | 王红 | Igniter used in a kind of medium-high frequency sintering firing equipment |
Also Published As
Publication number | Publication date |
---|---|
JP2008291728A (en) | 2008-12-04 |
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