Title of Invention

FULL-TRANSISTOR IGNITION APPARATUS .

Abstract

A full-transistor ignition apparatus is provided, by which an energizing time of the primary current of an ignition coil can be optimally controlled per each rotation and a necessary and minimum energizing time of the primary current can be obtained at the time of the lower rotation rate through at the time of the higher rotation rate. The apparatus has a primary current control section of the primary coil 23 comprising first and second CR circuits 31 and 32 having different time constants and having inverse charging and discharging timings; a comparator CP for comparing voltages of respective condensers C1 and C2; and a correction circuit 33 connected to one of the condensers C1. At the time of a higher rotation rate, a signal waveform of the first CR circuit 31 is transferred to the higher voltage direction, and a signal waveform of the second CR circuit 32 is inversely transferred to the lower voltage direction from the correction circuit 33 , so that a timing of crossing is hastened. The current is energized at an early timing at the time of a higher rotation rate compared to at the time of a lower rotation rate, and the primary current flows through the primary coil of an ignition coil only for an approximately same time period.

Full Text

FIELD OF THE INVENTION The present invention relates to an ignition apparatus for an engine, particularly relates to a technology that is effective for applying to a contactless full-transistor ignition apparatus for use in ignition of an engine. BACKGROUND OF THE INVENTION Conventionally, as to a full-transistor ignition apparatus for use in ignition of an engine, such a method is employed that the current has previously energized to the primary side (hereinafter, referred to as primary current) ; when the energy of the primary side of an ignition coil w which satisfies the equation of w=(L*I)/ 2 is enhanced, the current which has energized to the primary side is rapidly interrupted; back electromotive force is induced on the primary side of the ignition coil; and a high voltage generated on the secondary side at that time is made discharged at a spark plug and ignited to an air-fuel mixture within an engine. In a full-transistor ignition apparatus for use in ignition of an engine as the aforementioned one, for example, in the analog control of the primary current of the ignition coil, in a four- wheeled vehicle, a shape of the pickup coil is different from that for a two-wheeled vehicle, and like the primary current control circuit, between a pickup coil and a transistor for switching an ignition coil, dwell angle control circuit comprising a diode, a condenser and resistance is connected, and the operating point; of the transistor is changed by the generated voltage of the pickup coil and the charge stored in the condenser. In such a primary current control circuit, for example, at the time of lower rotation rate in the generated voltage of the pickup coil, the transistor could be turned off by slight negative voltage, to the contrary, at the time of higher rotation rate, the working voltage of the transistor is transferred to the larger negative voltage side. Therefore, as to switching on time of t.he transistor, as the rate becomes higher, the more dwell angle increases and the longer switching on time becomes. In this way, the dwell angle control is performed by utilizing the generation voltage of the pickup coil itself of a signal generator increasing with a rise of rotation rate and by lowering the operating point of the transistor with an increase of the generation voltage and the lowering of the generated second voltage of the ignition coil at the time of higher rotation rate is prevented. This has been explained hereinafter with reference to illustrative drawings. However, even in the analogue control of the primary current using the primary current control circuit as aforementioned, although an energizing time of an ignition coil is changed, it is difficult to energize only certain time at the time of a lower rotation rate through at the time of a higher rotation rate, since the primary current is made flown for a time longer than a time being necessary, it is required to add an ignition protection circuit, and it is estimated to wastefully consume the power. Specifically, since it is required that the primary current is made flown and interrupt per each rotation of an engine, the time for which the current can be flown to the ignition coil is limited by the number of rotations of the engine per certain time, for example, in order to generate a sufficient secondary voltage, it is necessary to flow the primary current only for a time on the order of 5 ms (millisecond) , however, at the time of a lower rotation rate, the current is made flown for a longer time such as for a time on the order of 60 ms. Moreover, in the case of a two-wheeled vehicle (analogue control), since an ignition advance angle range is determined by the width of a reluctor, it is difficult to employ a pickup as a conventional example employs. SUMMARY OF THE INVENTION Hence, an object of the present invention is to provide a full-transistor ignition apparatus for optimally controlling an energizing time of the primary current of an ignition coil per each rotation, being capable of obtaining the necessary and minimum primary current energizing time at the time of lower rotations per second through at the time of higher rotations per second, thereby utilizing a conventional ACG flywheel for a two-wheeler as it is and being capable of making the timing of the energizing initiation precise and suppressing the consuming power as well. The present invention utilizes a CR time constant of a condenser and a resistance, and the frequency characteristics of the CR circuit in the primary current control, and carries out comparison control and the optimum correction per one period. Specifically, a full-transistor ignition apparatus according to the present invention has comparison control means for comparing voltages of two sets of CR circuits having different time constants and having inverse charging discharging timings respectively and voltages of condensers of these two sets of CR circuits, when the voltage of one of condensers of the CR circuits is higher than that of the other condenser of the CR circuits, controlling the voltage so as to energize the primary current by switching a transistor for use in switching of the ignition coil on, and a correction control means, being connecting one condenser of the CR circuit, for performing the optimum correction per each rotation by utilizing a pulser signal and for optimally controlling an energizing time during which the primary current flows through the ignition coil. According to a full-transistor ignition apparatus of the present invention, the following advantages can be obtained: (1) Since an energizing time of the primary current can be optimally controlled per each rotation by having comparison control means for comparing and controlling voltages of two sets of CR circuits having the respective different time constants and inverse charging and discharging timings and voltages of condensers of these two sets of CR circuits and correction control means for performing optimal correction per each rotation by utilizing a pulser signal and optimally controlling an energizing time for energizing the primary current through an ignition coil, it is possible that a necessary and minimum energizing time of the primary current is obtained at the time of lower rotation rate through at higher rotation rate. (2) According to the aforementioned (1), a conventional flywheel of ACG for a two-wheeler can be utilized as it is. (3) According to the aforementioned (1), the initiation of energizing timing can be precisely performed by comparison and the optimal correction per each rotation and the consuming electric power can be suppressed. BRIEF DESCRIPTIONS OF THE ACCOMPANYIN DRAWINGS Fig. 1 is a functional block diagram showing a full-transistor ignition apparatus that is one embodiment of the present invention; Fig. 2 is a circuit diagram showing a primary current control section of a primary coil configuring a full-transistor ignition apparatus in one embodiment of the present invention; Fig. 3 is a timing diagram showing an operational waveform in the main section of a primary current control section of a primary coil in one embodiment of the present invention; Fig. 4A is an illustration showing a pickup coil and Fig. 4B is an illustration showing a flywheel for use in a two-wheeled vehicle in a full-transistor ignition apparatus according to one embodiment of the present invention; Fig. 5 is a circuit diagram showing a primary current control circuit in a full-transistor ignition apparatus which is the premise of the present invention ; and Fig. 6 is a timing diagram showing an operational waveform at the time of a lower rotation rate and at the time of a higher rotation rate in a full-transistor ignition apparatus that is the premise of the present invention. BACKGROUND ART In a full-transistor ignition apparatus for use in ignition of an engine as the aforementioned one, for example, in the analog control of the primary current of the ignition coil, in a four- wheeled vehicle, a shape of the pickup coil is different from that for a two-wheeled vehicle as shown in Fig. 4A (a: for a four wheeled vehicle, b: for a two-wheeled vehicle), and like the primary current control circuit shown in Fig. 5, between a pickup coil and a transistor for switching an ignition coil, dwell angle control circuit comprising a diode, a condenser and resistance is connected, and the operating point of the transistor is changed by the generated voltage of the pickup coil and the charge stored in the condenser. In such a primary current control circuit, for example, as shown in Fig. 5, at the time of lower rotation rate in the generated voltage of the pickup coil, the transistor could be turned off by slight negative voltage, to the contrary, at the time of higher rotation rate, the working voltage of the transistor is transferred to the larger negative voltage side. Therefore, as to switching on time of the transistor, as the rate becomes higher, the more dwell angle increases and the longer switching on time becomes. In this way, the dwell angle control is performed by utilizing the generation voltage of the pickup coil itself of a signal generator increasing with a rise of rotation rate and by lowering the operating point of the transistor with an increase of the generation voltage and the lowering of the generated second voltage of the ignition coil at the time of higher rotation rate is prevented. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiment of the present invention will be described based on the appended drawings. Fig. 1 is a functional block diagram showing a full-transistor ignition apparatus which is one embodiment of the present invention, Fig. 2 is a circuit diagram showing a primary current control section of a primary coil configuring a full-transistor ignition apparatus in one embodiment of the present invention and Fig. 3 is a timing diagram showing an operational waveform in the main section of primary current control section of a primary coil in one embodiment of the present invention. First, according to Fig. 1, one example of a configuration of a full-transistor ignition apparatus in the present embodiment of the present invention will be described below. A full-transistor ignition apparatus of the present embodiment is, for example, employed for an engine for a two-wheeled vehicle, comprises an AC3 coil 1, a pulser coil 2, a control circuit 3, an ignition coil 4, a spark plug 5 and the like and is configured so that a wave signal outputted from the ACG coil 1 and the pulser coil 2 is inputted into the control circuit 3. The voltage generated in the control circuit 3 is supplied to the primary coil of the ignition coil 4 and the secondary voltage generated in the second coil at the time of interruption of the primary current is discharged at the spark plug 5. The control circuit 3 comprises a regulator/rectifier 11, an electric source section for the primary coil 12, an electric source section for control circuit 13, a control section 14, a power transistor 15 and the like. In the control section 14, an ignition timing range control section 21, an advance angle control circuit 22 , a primary current control section of a primary coil 23 and the like are provided. The regulator/rectifier 11 is connected to an input terminal of the ACG coil 1. An ACG signal is outputted from the ACG coil 1 and the current is rectified by the ACG signal as an input. The rectified voltage is outputted to the electric source section for the primary coil 12 and to the electric source section for the control circuit 13. The electric source section for the primary coil 12 is connected to an output of the regulator/rectifier 11. The voltage outputted from the regulator/rectifier 11 is made as an input and, based on this voltage, a voltage for supplying to the primary coil of the ignition coil 4 is generated. The generated voltage is outputted to the output terminal to which the primary coil of the ignition coil 4 is connected. The electric source section for the control circuit 13 is connected to an output of the regulator/rectifier 11, in parallel with the electric source for the primary coil 12. A voltage outputted from the regulator/rectifier 11 is made as an input and, based on this voltage, a voltage for operating the control section 14 is generated. The generated voltage is outputted to a connection terminal of the control section 14. In the control section 14, the ignition timing range control section 21 is connected to an input terminal of the pulser coil 2 via a connection terminal of the control section 14. A pulser signal outputted from the pulser coil 2 is made as an input and, based on the pulser signal, an ignition timing range signal is generated. The generated ignition timing range signal is outputted to the advance angle control circuit 22 and the primary current control section of the primary coil 23. The advance angle control circuit 22 is connected to an output of the ignition timing range control section 21 as well as connected to an input terminal of the pulser coil 2 via a connection terminal of the control section 14 that is parallel with the ignition timing control section 21. A pulser signal outputted from the pulser coil 2 and an ignition timing range signal outputted from the ignition timing range control section 21 are made as inputs, and an ignition advance control signal is generated based on these pulser signal and ignition timing range signal. The ignition control signal is outputted to the primary current control section of the primary coil 23. The primary control section of the primary coil 23 is connected to outputs of the ignition timing range control section 21 and the advance angle control circuit 22, respectively, as well as connected to an input terminal of the pulser coil 2 via a connection terminal of the control section 14 which is parallel with the ignition timing range control section 21 and the advance angle control circuit 22. A pulser signal outputted from the pulser coil 2, an ignition timing range signal outputted from the ignition timing range control section 21 and an ignition advance control signal outputted from the advance angle control circuit 22 are made as inputs and, based on these pulser signal, ignition timing range signal and ignition advance control signal, a primary current control signal of the primary coil is generated, so that the primary current control signal of the primary coil is outputted to the base of the power transistor 15 via a connection terminal of the control section 14. As to the power transistor 15, its base is connected to a connection terminal of the control section 14 that is connected to an output of the primary current control section of the primary coil 23, its collector is connected to an output terminal to the ignition coil 4 , and its emitter is connected to the grounded voltage, respectively. The power transistor 15 is controlled by a primary current control signal of the primary coil outputted from the primary current control section of the primary coil 23. When the voltage level of a primary current control signal of the primary coil is high, the power transistor 15 is switched on, collector current flows, so that the primary current flows to the primary coil of the ignition coil 4. On the contrary, when the voltage level of a primary current control signal of the primary coil is low, the power transistor 15 is switched off. Next, according to Fig. 2, one example of a configuration of the primary current control section of the primary coil 21 configuring a full-transistor ignition apparatus of the present embodiment of the present invention will be described in detail below. The primary current control section of the primary coil 23 of the present embodiment comprises a plurality of transistors TR1 to TR6 (TR1, TR3 and TR6 are NPN type transistors, TR2, TR4 and TR5 are of PNP type transistors), a plurality of condensers C1 and C2, a plurality of resistors Rl to R20, a plurality of diodes Dl and D2, a comparator CP and the like. The primary current control section of the primary coil 23 is so configured that a pulser signal outputted from the pulser coil 2 , an ignitior timing range signal outputted from the ignition timing range control section 21, an ignition advance control signal outputtec from the advance angle control circuit 22 are inputted respectively, a primary current control signal of the primary coil is outputted from the power transistor 15, and the electric source is supplied from the electric source for the control circuit 13. The primary current control section of the primary coil 23 has , particularly as two sets of CR circuits having respective different time constants and inverse charging and discharging timings, a first CR circuit 31 comprising the condenser C1 and the resistors R7 to R9 and a second CR circuit 32 comprising of the condenser C2 and the resistors R10 to R12. The primary current control section of the primary coil 23 further has a comparator CP as comparison control means for comparing the voltages of the condenser C1 and the condenser C2. When the voltage of the condenser C1 is higher than that of the condenser C2, the comparator CP switches the power transistor 15 on, which is in charge of switching of the ignition coil 4, and controls to energize the primary current to the primary coil. In the primary current control section of the primary coil 23, a timing of switching on the comparator CP can be changed by utilizing the difference of frequency characteristics of the respective CR circuits. However, if only frequency characteristics is used, the optimum energizing time of the primary current cannot be obtained at the time of the lower rotation rate through at the time of the higher rotation rate. Then, further the optimum correction per each rotation is performed to one of the condensers, i.e., the condenser C1 by utilizing a pulser signal, and a correction circuit 33 comprising the transistor TR4 and the resistor R12 is provided as correction control means for optimally controlling an energizing time to energize the primary current to the primary coil of the ignition coil 4. An operation of the primary current control section of the primary coil 23 configured above will be described below on the basis of the timing diagram showing an operating waveform of Fig. 3. A pulser signal outputted from the pulser coil 2 is inputted into a node A of the primary current control section of the primary coil 23 . The pulse signal is a pulse wave generated at the most advanced time when the range in which an ignition control is performed is the most advanced, and at the most delayed time when the range in which an ignition control is performed is the most delayed. A waveform in each single pulse wave shape is positive at the most advanced time and negative at the most delayed time. Charging and discharging are carried out in the first CR circuit 31 and the second CR circuit 32, respectively, on the basis of a pulser signal in each signal pulse shape, which is positive at the most advanced time and negative at the most delayed time. In one of the CR circuits, i.e., the first CR circuit 31, like a voltage waveform of a node B, charging is initiated at the generation timing of negative pulse wave, and charging is continued until the positive pulse wave is generated. Then, charging is switched into the discharging by the generation timing of the positive pulse wave, and discharging is continued until the negative pulse wave is generated. At this moment, charging is determined by a time constant of the condenser C1 and the resistances R8 and R9 for dividing voltages when the TR1 and TR2 of the transistors are switched on. Moreover, discharging is determined by a time constant of the condenser C1 and the resistant R7 when the transistor TR3 is switched on. In the other second CR circuit 32 , like a voltage waveform of a node C, charging is initiated at the generation timing of the positive pulse wave, and the charging is continued until the negative pulse wave is generated. Then, charging is changed to discharging at the generation timing of the negative pulse wave, and discharging is continued until the positive pulse wave is generated. At this moment, charging is determined by a time constant of the condenser C2 and the resistors R10 and Rll for dividing voltages when the TR1 and TR2 of the transistors are switched on. Moreover, discharging is determined by a time constant of the condenser C2 and the resistant R12 when the transistor TR4 is switched on. Since each signal of the node B and C that is changed as described above is inputted into the comparator CP, the comparator CP outputs a signal when the signal level of the node B exceeds over the signal level of the node C. While a signal is outputted from this comparator CP, the transistor TR5 is switched on, the signal at this moment becomes a control signal of the power transistor 15, then, the primary current flows through the primary coil of the ignition coil 4 when the power transistor 15 is switched on and on the contrary, the primary current does not flow when the power transistor 15 is switched off. At this moment, a waveform of the primary current which flows through the primary coil of the ignition coil 4 is a waveform as shown in Fig. 3. Specifically, per each cycle, the current increases from the timing when a signal B and a signal C are crossed, and it becomes certain level at the predetermined current. For this certain time, for example, only for a time on the order of 5 ms, the current flows through the primary coil of the ignition coil 4. After this certain time passes, the timing when the primary current is interrupted is an ignition timing. Moreover, a time from the time when the primary current is made low level until the time when the signal B and the signal C are crossed is an off time of the primary current. Moreover, since the timing when the signal B and the signal C are crossed can be obtained by comparing voltage waveforms of the first CR circuit 31 and the second CR circuit 32 each other, the timing is changed corresponding to the rotation rate of an engine . Specifically, at the time of higher rotation rate, as shown with alternate long and short dash lines in Fig. 3, the waveform of the node B is transferred to higher voltage direction, and the waveform of the node C is inversely transferred to lower voltage direction by the correction circuit 33, the timing when the signal B and the signal C are crossed is hastened and the ignition advance control is carried out. Specifically, as to the signal C, in the case where the correction circuit 33 is absent, the signal C is transferred to higher voltage direction just like the signal B, but by providing the correction circuit 33 comprising transistor TR4 utilizing a pulser signal and the resistor R12, for a split second when the positive side on which a pulser is generated is generated, the transistor TR4 is switched on and the resistor R12 is connected, discharging is carried out by changing the time constant and the waveform can be lowered by the rise of rotation rate. Owing to this, the timing of the current increasing of the waveform of the primary current at the time of higher rotation rate is hastened compared to that at the time of lower rotation rate (continuous line). It is energized at an earlier timing compared to at the time of lower rotation rate, and the primary current can be flown through the primary coil of the ignition coil 4 only for an approximately same time period on the order of 5 ms. In this way, the primary current has been previously energized through the primary coil of the ignition coil 4 only for the optimum time period corrected per each rotation at the lower rotation rate through at the higher rotation rate. When the energy of the primary coil of the ignition coil 4 is enhanced, the primary current energized through the primary coil of the ignition coil 4 is rapidly interrupted. A back electromotive force is induce in the primary coil of the ignition coil 4 and, at this moment, high voltage generated on the secondary coil of the ignition coil 4 is discharged at the spark plug 5, so that the mixture within an engine can be ignited. Therefore, according to a full-transistor ignition apparatus of the present embodiment of the present invention, an energizing time of the primary current can be optimally corrected per each rotation and the energizing time of the primary current can be optimally controlled by providing the primary current control section of the primary coil 23 including the first CR circuit 31 and second CR circuit 32; the comparator CP for comparing voltages of the respective condenser C1 and condenser C2; and the correction circuit 33 connected to one of the condensers, i.e., the condenser C1. Therefore, it is capable of obtaining a necessary and minimum energizing time of the primary current at the lower rotation rate through at the higher rotation rate. It goes without saying that the present invention is not limited to the embodiment aforementioned and various modifications may be made without departing from the scope of its intention of the invention. WE CLAIM: 1. A full-transistor ignition apparatus, said apparatus comprising: a first CR circuit and a second CR circuit having different time constants and having inverse charging and discharging timings, respectively; comparison and control means for comparing voltage of a condenser of said first CR circuit and voltage of a condenser of said second CR circuit and controlling so as to energize the current through the primary coil by switching on a transistor for switching an ignition coil when voltage of a condenser of said first CR circuit is higher than voltage of a condenser of said second CR circuit; and correction and control means, being connected to the condenser of said second CR circuit, for optimally correct per each rotation by utilizing a pulser signal and for optimally controlling an energizing time for energizing the current through the primary coil of said ignition coil. 2. A full-transistor ignition apparatus, substantially as herein described, particularly with reference to the accompanying drawings. A full-transistor ignition apparatus is provided, by which an energizing time of the primary current of an ignition coil can be optimally controlled per each rotation and a necessary and minimum energizing time of the primary current can be obtained at the time of the lower rotation rate through at the time of the higher rotation rate. The apparatus has a primary current control section of the primary coil 23 comprising first and second CR circuits 31 and 32 having different time constants and having inverse charging and discharging timings; a comparator CP for comparing voltages of respective condensers C1 and C2; and a correction circuit 33 connected to one of the condensers C1. At the time of a higher rotation rate, a signal waveform of the first CR circuit 31 is transferred to the higher voltage direction, and a signal waveform of the second CR circuit 32 is inversely transferred to the lower voltage direction from the correction circuit 33 , so that a timing of crossing is hastened. The current is energized at an early timing at the time of a higher rotation rate compared to at the time of a lower rotation rate, and the primary current flows through the primary coil of an ignition coil only for an approximately same time period.

Documents:

137-cal-2001-granted-abstract.pdf

137-cal-2001-granted-claims.pdf

137-cal-2001-granted-correspondence.pdf

137-cal-2001-granted-description (complete).pdf

137-cal-2001-granted-drawings.pdf

137-cal-2001-granted-examination report.pdf

137-cal-2001-granted-form 1.pdf

137-cal-2001-granted-form 18.pdf

137-cal-2001-granted-form 2.pdf

137-cal-2001-granted-form 3.pdf

137-cal-2001-granted-form 5.pdf

137-cal-2001-granted-gpa.pdf

137-cal-2001-granted-priority document.pdf

137-cal-2001-granted-reply to examination report.pdf

137-cal-2001-granted-specification.pdf

137-cal-2001-granted-translated copy of priority document.pdf