Multiple spark capacitive discharge ignition system for an internal combustion engine

Information

  • Patent Grant
  • 6167875
  • Patent Number
    6,167,875
  • Date Filed
    Monday, November 30, 1998
    26 years ago
  • Date Issued
    Tuesday, January 2, 2001
    23 years ago
Abstract
An ignition system for an internal combustion engine that generates more ignition sparks per ignition event, i.e., per cylinder, per cycle, when the engine is operated in the stratified fuel injected mode than when the engine is operated in the homogeneous fuel injection mode.
Description




FIELD OF THE INVENTION




The invention relates to ignition systems for internal combustion engines, and particularly, to a multiple spark capacitive discharge ignition system for such an engine.




In internal combustion engines, it is known that the physical nature of the fuel or fuel/air charge injected into the cylinder varies depending upon engine operating conditions. Specifically, at low engine speeds, the fuel charge is injected into the cylinder in the form of a stratified cloud of fuel particles. The cloud of fuel particles is termed stratified because the density of the fuel particles within the cloud is not constant, i.e., not homogeneous throughout the charge. At higher engine speeds, the fuel charge is injected into the cylinder in what is termed to be a “homogeneous” cloud of fuel particles. The charge is termed homogeneous because the density of fuel particles in the fuel charge is relatively constant throughout the charge.




A single ignition spark or a small number of ignition sparks anywhere within a homogeneous fuel charge will cause complete combustion of the fuel charge. This is not so for a stratified fuel charge. With a stratified injection of fuel, it has been found desirable to provide a greater number of ignition sparks (than is provided under homogeneous conditions) in order to ensure that the stratified fuel charge is adequately or completely ignited. U.S. Pat. Nos. 5,170,760 and 4,653,459 generally illustrate ignition systems for providing a plurality of ignition sparks to ignite a stratified or non-homogeneous fuel charge in the cylinder.




SUMMARY OF THE INVENTION




The invention provides an ignition system for an internal combustion engine having one or more cylinders. The ignition system generates more ignition sparks per ignition event when the engine is operated in the stratified fuel injected mode than when the engine is operated in the homogeneous fuel injection mode. Generally speaking, the system includes an electronic control unit (“ECU”) for generating ignition signals for the respective cylinders, an input/logic multiplexer for multiplexing the ECU control signals, a direct current to direct current (“DC—DC”) converter for charging an ignition capacitor, a silicon controlled rectifier (“SCR”) for discharging the ignition capacitor, an ignition trigger circuit for triggering the SCR and an ignition distribution network for distributing the energy discharged from the ignition capacitor to the appropriate ignition coil.




The DC—DC converter includes a pulse width modulator which generates, in response to the inputs from the ECU, a high frequency output of at least 1000 hertz frequency. Preferably, however, the frequency of the pulse width modulator output is 3.0 khz. The pulse width modulator drives a series of parallel connected high power insulated gate bipolar transistors (“IGBTs”) connected through a transformer to a power supply. The power supply voltage is generated by the alternator. Energizing of the transistors by the pulse width modulator at a rate of approximately 3.0 khz causes a flyback voltage to be generated at the primary of the transformer. The flyback voltage is, through mutual inductance, transferred to the secondary of the transformer and “stepped-up” to approximately 200 to 300 volts. This voltage charges an ignition capacitor to approximately 200 to 300 volts. The ignition capacitor is selectively discharged by triggering the SCR to provide electrical energy to the ignition coil which generates a spark to ignite the fuel charge.




The current flowing through the IGBTs is monitored using a current sensing resistor connected in series with the IGBTs. The voltage across the current sensing resistor is “fed back” to the pulse width modulator. The pulse width modulator varies the width of the output pulses generated by the pulse width modulator to compensate for variations in the voltage of the power supply. Thus, as the voltage supplied by the alternator increases, the pulse width of the output of the pulse width modulator decreases. This allows the ignition system to operate effectively from a low voltage of approximately eight volts (which occurs upon engine cranking) to a high voltage of approximately 30 volts (which occurs during high speed engine operation). The use of current sensing to indirectly sense the variations of the supply voltage eliminates the need to compensate the ignition system for variations in the temperature of the system.




It is an advantage of the invention to provide a capacitive discharge ignition system that, in general, energizes the engine spark plug or spark plugs at a higher energy level or for a longer duration when the engine is operating under stratified fuel injection conditions than when the engine is operating under homogeneous engine operating conditions.




It is another advantage of the invention to provide an ignition system that increases the number of strike opportunities per ignition event when the fuel charge is stratified relative to when the fuel charge is homogeneous.




It is another advantage of the invention to provide the ignition sparks at a rate which at least exceeds 1000 hertz.




It is another advantage of the invention to provide an ignition system for an internal combustion engine that utilizes as its voltage source the voltage from the alternator.




It is another advantage of the invention to provide an ignition system for an internal combustion engine that utilizes a transformer which can accommodate larger voltage ranges.




It is another advantage of the invention to provide an ignition system for an internal combustion engine that charges the ignition capacitor using a flyback voltage.




It is another advantage of the invention to provide an ignition system which senses the current flowing through the transformer to eliminate the need for temperature compensation of the ignition system and improve the efficiency of the ignition system.




Other features and advantages of the invention are set forth in the following detailed description and claims.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a partial cross section of an internal combustion engine embodying the engine.





FIG. 2

is a block diagram of the ignition system for the internal combustion engine.





FIG. 3

is a detailed schematic of the input/logic multiplexer of the ignition system.





FIG. 4

is a detailed schematic of the DC—DC converter of the ignition system.





FIG. 5

is a detailed schematic of the ignition trigger circuit of the ignition system.





FIG. 6

is a detailed schematic of the ignition distribution circuit of ignition system.





FIG. 7

is a chart which plots ignition coil on time as a function of engine speed and throttle position.





FIG. 8

is a chart which plots the maximum ignition coil on time for a given engine speed.











Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.




DESCRIPTION OF THE PREFERRED EMBODIMENT




Partially shown in

FIG. 1

of the drawings is an internal combustion engine


10


embodying the invention. Although any internal combustion engine is appropriate, the internal combustion engine of the preferred embodiment is a two-stroke, direct injected, internal combustion engine having six cylinders (illustrated schematically and labelled


1


-


6


in FIG.


6


). Cylinder


1


of the engine is illustrated in detail in FIG.


1


. The engine


10


includes a crankcase


14


defining a crankcase chamber


18


and having a crankshaft


22


rotatable therein. An engine block


26


defines the cylinder


1


. The engine block


26


also defines an intake port


30


communicating between the cylinder


1


and the crankcase chamber


18


via a transfer passage


34


. The engine block


26


also defines an exhaust port


38


. A piston


42


is reciprocally movable in the cylinder


1


and is drivingly connected to the crankshaft


22


by a crank pin


46


. The cylinder head


50


closes the upper end of the cylinder


1


so as to define a combustion chamber


54


. A spark plug


58


is mounted on the cylinder head


50


and extends into the combustion chamber


54


.




As shown schematically in

FIG. 2

of the drawings, the internal combustion engine


10


also includes an ignition system


62


for providing an ignition spark to the spark plug


58


to ignite fuel in the cylinders


1


-


6


. The ignition system


62


illustrated in

FIG. 2

may be used in an internal combustion engine having any number of cylinders. In the preferred embodiment of the invention, the ignition system


62


generates a plurality of ignition sparks (per cylinder, per cycle) when the fuel charge injected into the cylinder is stratified, and generates fewer sparks (per cylinder, per cycle) when the fuel charge injected into the cylinder is homogeneous.




In general terms, the ignition system


62


includes an electronic control unit (“ECU”)


66


, an input/logic multiplexer


70


(shown in detail in FIG.


3


), a direct current to direct current (“DC—DC”) converter


74


(shown in detail in FIG.


3


), an ignition trigger circuit


78


(shown in detail in FIG.


4


), a silicon controlled rectifier (“SCR”)


82


, and an ignition distribution circuit


86


(shown in detail in FIG.


6


).




Any ECU for an internal combustion engine could be used to operate the ignition system


62


. The ECU


66


generates an ignition control signal for each of the cylinders of the engine. In the embodiment of the engine shown in the drawings, the engine is a six cylinder engine and, accordingly, the ECU


66


generates six ignition control signals, i.e., one ignition control signal per engine cycle for each of the six cylinders.





FIG. 3

illustrates the input/logic multiplexer


70


of the ignition system


62


. As shown in

FIG. 3

, the ignition control signals from the ECU


66


(for cylinders one through six) are input to the input/logic multiplexer


70


on input lines


90


,


94


,


98


,


102


,


106


, and


110


. The input lines


90


,


94


,


98


,


102


,


106


, and


110


are connected to inverters


114


,


118


,


122


,


126


,


130


, and


134


, respectively. The inverters


114


,


118


,


122


,


126


,


130


, and


134


have outputs


138


,


142


,


146


,


150


,


154


and


158


, respectively. The outputs


138


,


142


and


146


are connected to OR gate


162


and the outputs


150


,


154


and


158


are connected to OR gate


166


. The outputs


170


and


174


of the OR gates


162


and


166


, respectively, are connected to OR gate


178


and to OR gate


182


. The input/logic multiplexer


70


also includes a delay circuit


190


connected to the output


194


of OR gate


178


. The delay circuit


190


includes resistor R


24


, diode D


10


, capacitor C


1


and resistor R


1


. The output of the delay circuit is connected to the input of OR gate


182


to completely combine or multiplex the ignition control signals from the ECU


66


. The output of OR gate


182


is connected to NAND gate


186


through resistor R


9


. A capacitor C


26


is connected to ground and to the inputs of NAND gate


186


. Resistor R


9


and capacitor C


26


form a time delay circuit. The time delay created by R


9


and C


26


allows the capacitor C


10


to completely discharge before receiving a subsequent energy pulse from the pulse width modulator


206


. If the time delay were not provided, the subsequent energy pulse from the pulse width modulator


206


would reach SCR


82


during the discharge of energy from the capacitor C


10


. This would result in SCR


82


being “held open” by the signal from the pulse width modulator


206


.





FIG. 4

illustrates the DC—DC converter


74


of the ignition system


62


. The DC—DC converter


74


includes a pulse width modulator


206


. The pulse width modulator


206


is a conventional component that is commercially available from a number of manufacturers. In the preferred embodiment, the pulse width modulator


206


is manufactured by National Semiconductor, Inc. and is marketed under part number LM2578. As shown in

FIG. 4

, the output


198


of NAND gate


186


is connected via node B to the oscillating input


202


(pin 3 of the LM2578 chip package) of pulse width modulator


206


through an RC circuit comprising resistors R


2


, R


14


and R


15


, capacitors C


6


and C


7


, and a diode D


11


. The pulse width modulator


206


also includes an inverted input


208


(pin 1 of the LM2578 chip package). In the preferred embodiment, pins 5 and 7 of the LM2578 chip package are connected to ground. The pulse width modulator


206


also has an output


210


(pin 6 of the LM2578 chip package) that is connected to a parallel connected bank of insulated gate bipolar transistors (“IGBTs”) Q


1


, Q


2


and Q


3


, through NAND gate


214


, and through a resistive network including resistors R


13


, R


53


, R


17


and diode D


18


.




As shown in the drawings, the IGBTs Q


1


, Q


2


and Q


3


include gates


218


,


222


, and


226


, drains


230


,


234


and


238


, and sources


242


,


246


and


250


, respectively. The gates


218


,


222


and


226


are connected (through the resistive network) to the output of the NAND gate


214


, and the drains


230


,


234


and


238


are connected through resistors R


20


, R


21


and R


22


, respectively, to one end


254


of the primary winding


258


of a transformer


262


. The sources


242


,


246


, and


250


are connected to ground via serially connected resistors R


11


and R


10


, and are also connected to the inverted input


208


of pulse width modulator


206


.




The opposite end


264


of the primary winding


258


is connected to a voltage source +V. In the preferred embodiment of the invention, the voltage source +v is the output of the internal combustion engine alternator (not shown). The transformer


262


also includes a secondary winding


266


connected at one end


270


to ground and at the opposite end


274


to diode D


9


and ignition capacitor C


10


through diode D


8


. The ignition capacitor C


10


is connected to the anode


278


of the SCR


82


. In the preferred embodiment, the transformer is a 1:2 step up transformer.





FIG. 5

illustrates the ignition trigger circuit


78


of the ignition system


62


. The ignition trigger circuit


78


includes an OR gate


282


having inputs


286


and


290


connected to the output of OR gate


178


via node A. The output


294


of the OR gate


282


is connected through an RC circuit including capacitor C


28


and resistor R


16


to a first input


298


of OR gate


302


. The second input


306


of the OR gate


302


is connected to the output


210


of the pulse with modulator


206


through OR gate


310


, an RC circuit including capacitor C


29


and resistor R


48


, NAND gate


314


and an RC circuit consisting of resistor R


49


, capacitor C


30


and resistor R


50


. The output


318


of the OR gate


302


is connected to one input


322


of NAND gate


326


. The other input


330


of NAND gate


326


is connected to the output of OR gate


178


from the input/logic multiplexer


70


via node A. The output


334


of the NAND gate


326


is connected through an RC circuit including resistors R


52


and R


51


and capacitor C


31


to the primary winding


338


(

FIG. 5

only) of isolation transformer


342


(shown in FIGS.


4


and


5


). Secondary winding


346


(

FIG. 4

only) of the isolation transformer


342


is connected in parallel to diode D


31


and to the triggering gate


350


of the SCR


82


. The cathode


354


of the SCR


82


is connected via node D to the ignition distribution circuit


86


of the ignition system


62


.




Referring to

FIG. 6

, the ignition distribution circuit


86


includes ignition triggering modules


358


,


362


,


366


,


370


,


374


and


378


, for each of the internal combustion engine cylinders


1


,


2


,


3


,


4


,


5


and


6


, respectively. Each of the modules is identical and accordingly only the module


358


will be described in detail. The cathode


354


of SCR


82


is connected to the anode


382


of SCR


386


. The input


390


to the module


358


is connected to the ECU


66


to receive the ECU ignition control signal for cylinder


1


. The input


390


is connected to the base


394


of transistor Q


4


through the RC circuit which includes resistor R


45


and capacitor C


12


. The transistor Q


4


includes an emitter


398


connected to a voltage supply


402


and a collector


406


connected to ground through resistor R


46


. The collector


406


is also connected to the gate


410


of the SCR


386


through the RC circuit including resistor R


47


, diode D


6


, capacitor C


22


and resistor R


12


. The SCR


362


includes a cathode


414


that is connected to capacitor C


22


and resistor R


12


and to ignition coil


58


and diode


418


for the cylinder


1


.




Though other components and arrangements of components are possible, the resistors and capacitors employed in the preferred embodiment have the following values.




R


1


—510 Kohm, ⅛/watt;




R


2


-R


8


, R


14


, R


18


, R


24


—1 Kohm, ⅛ watt;




R


10


, R


11


, R


20


-R


22


—0.01 ohm, 2 watt;




R


12


, R


28


, R


32


, R


36


, R


40


, R


44


—100 ohm, ⅛ watt;




R


13


, R


53


—47 ohm, ¼ watt;




R


15


, R


17


—24 ohm, ⅛ watt;




R


16


—82 Kohm, ⅛ watt;




R


19


, R


26


, R


30


, R


34


, R


38


, R


42


, R


46


—10 Kohm, ⅛ watt;




R


25


, R


29


, R


33


, R


37


, R


41


, R


45


—3.3 Kohm, ⅛ watt;




R


27


, R


31


, R


35


, R


39


, R


43


, R


47


—56 ohm, ⅛ watt;




R


48


—249 Kohm, ⅛ watt;




R


49


—5.1 Kohm, ⅛ watt;




R


50


—750 Kohm;




R


51


, R


52


—150 ohm, ⅛ watt;




C


1


, C


28


-C


30


—0.001 microfarad;




C


2


, C


4


, C


5


—100 picofarad;




C


3


—330 microfarad;




C


6


—4700 picofarad;




C


7


, C


8


, C


9


, C


11


-C


13


, C


15


—0.022 microfarad;




C


10


—0.68 microfarad;




C


14


, C


17


-C


24


, C


31


-C


36


—0.1 microfarad;




C


16


, C


25


—100 microfarad.




The selection of the particular gates, diodes, SCRs, transistors and other components (employed in the ignition system


62


) is within the realm of one of ordinary skill in the art.




In operation, the inputs


90


,


94


,


98


,


102


,


106


and


110


are normally at a high voltage level (typically five volts and referred to variously as “high” or “logical ‘1’”). In order to generate an ignition control signal at a particular input


90


,


94


,


98


,


102


,


106


or


110


, the ECU


66


“pulls” the input to a low voltage level (typically zero volts and referred to variously as “low” or “logical ‘0’”). The inputs


90


,


94


,


98


,


102


,


106


and


110


are inverted by inverters, respectively, and the ouputs of the inverters are “combined” or multiplexed by OR gates


162


,


166


,


178


and


182


and are buffered by NAND gate


186


for inputting to the DC—DC converter


74


. The output of the OR gate


178


is also input to the ignition trigger circuit


78


and to OR gate


182


through delay circuit


190


. The delay circuit


190


creates a time delay that allows the pulse width modulator


206


to continue to run even after the ignition control signal attributable to the previous cycle returns to the high condition. This assures that the ignition capacitor C


10


remains charged for the beginning of the current cycle, i.e., when the next ignition control signal from the ECU


66


“goes low”.




In response to the output of the input/logic multiplexer


70


(from NAND gate


186


) the pulse width modulator


206


generates, on output


210


, an oscillating signal having a frequency of approximately between 1000 hertz and 4500 hertz, but which frequency is preferably approximately 3000 hertz (hz). The oscillating signal drives transistors Q


1


, Q


2


, and Q


3


at the 3000 hz frequency causing current from the alternator to flow through the primary winding


258


of the transformer


262


.




The rapid switching of the current through the transformer


262


generates a flyback voltage that is multiplied and transmitted, through mutual inductance of the transformer


262


, to the secondary winding


266


of the transformer


262


. The voltage appearing at the secondary winding


266


is approximately 200 to 300 volts. This voltage is stored momentarily by the ignition capacitor C


10


until the ignition capacitor C


10


is discharged by triggering of SCR


82


.




The current flow through the primary winding


258


of transformer


262


is monitored by placing current sensing resistors R


10


and R


11


in the current flow path and inputting the voltage across the resistors R


10


and R


11


to the inverted input


208


of pulse width modulator


206


. The pulse width of the pulse width modulator output


210


is changed or modulated in response to this voltage so that the ignition system


62


is effective through a wide range of alternator voltages, i.e., in the preferred embodiment, the alternator voltage range (through which the ignition circuit


62


is effective) is approximately 8 volts to approximately 30 volts. In effect, at low alternator voltages, the pulse width of the output


210


of the pulse width modulator


206


is increased to assure sufficient charge voltage for the ignition capacitor. As the alternator voltage rises, the pulse width of the output


210


of the pulse width modulator


206


decreases. At the beginning of a cycle, the initial trigger for the SCR


82


is generated by the ignition trigger circuit


78


because there is no output


210


from the pulse width modulator


206


to trigger (via trigger circuit


78


) the SCR


82


. After the initial triggering event, the pulse width modulator output


210


, which is connected to the SCR


82


through the ignition trigger circuit


78


, is used to trigger the discharge of the ignition capacitor C


10


.




The ignition control signals from the ECU


66


are input to the appropriate ignition distribution modules of the ignition distribution circuit


86


. When a particular ignition control signal is generated by the ECU


66


, the ignition control signal triggers the SCR of the respective ignition distribution module and that SCR is “held” open until the ignition control signal is turned off by the ECU


66


. As long as the ignition distribution module SCR is held open, the energy discharged from the ignition capacitor C


10


is transmitted directly to the ignition coil and spark plug connected to that ignition distribution module.




The ignition system is capable of generating a varying number of ignition sparks at the spark plug to increase or decrease the total spark duration according to various engine operating conditions such as engine speed, engine load, throttle position etc. Though various combinations of desired total spark duration as a function of engine operating conditions are appropriate depending upon the circumstances, the desired total spark duration of the preferred embodiment is determined as a function of both the engine speed and the throttle position as set forth in the chart shown in FIG.


7


. Moreover, while the invention has been described in terms of generating a higher number of sparks under stratified engine operating conditions, the higher energy level could also be provided under stratified engine operating conditions in the form of a longer spark duration or a higher spark voltage or a combination of longer spark duration, higher spark voltage and higher number of sparks.




As shown in

FIG. 7

, on the “Y” axis of the chart, the numbers zero through one thousand represent relative throttle positions, zero representing the idle position of the throttle, and one thousand representing wide open throttle. The numbers along the “X” axis represent the speed of the engine as measured in crankshaft rotations per minute. The numbers in the body of the chart represent ignition spark on time measured in milliseconds.




Generally, the chart shows a trend toward decreasing the total spark duration (ignition coil on time) with increasing engine speed and with increasing throttle position. Based on the ignition coil on times shown in the chart, the highest number of sparks attained, with the pulse width modulator


206


operating at approximately 3000 hertz, is approximately fifteen (at 5.0 ms of ignition coil on time, e.g., at idle throttle position and 200 rpm), and the lowest number of sparks attained is one (at 0.1 ms of ignition coil on time, e.g., at 500 throttle position and 1100 rpm). At wide open throttle and 7000 rpm, two ignition sparks are generated (0.5 ms of ignition coil on time).




Though, as stated above, there is a general trend toward decreasing the ignition coil on time with increasing speed and increasing throttle position, the ignition coil on time does not decrease continuously with increasing speed and increasing throttle position. Rather, there exist some discontinuities in the general trend toward decreasing ignition coil on time with increasing engine speed and increasing throttle position. These discontinuities exist as a result of empirical evidence that the precise ignition coil on times shown in the chart result in improved engine performance.





FIG. 8

is a chart illustrating the maximum ignition coil on time allowed. Exceeding these on times will result in overlap of the ignition event between cylinders.




Various features and advantages of the invention are set forth in the following claims.



Claims
  • 1. An ignition circuit for an internal combustion engine, comprising:a transformer having a primary winding connected to a voltage source and a secondary winding; a capacitive discharge ignition circuit, having a single ignition capacitor device coupled to the transformer secondary winding; and an electronic circuit for repetitively generating a flyback voltage on the primary winding of the transformer that is coupled to the secondary winding for charging the single ignition capacitor device, wherein the ignition circuit is operable to produce a plurality of ignition sparks in a spark plug each combustion cycle from the single ignition capacitor device in order to ignite the fuel charge in a cylinder, the electronic circuit being adapted to generate a greater number of sparks during each combustion cycle when a fuel charge in the cylinder is stratified than when the fuel charge in the cylinder is homogeneous.
  • 2. The ignition circuit as recited in claim 1, wherein the single ignition capacitor device is a single capacitor.
  • 3. The ignition circuit as recited in claim 1, wherein the ignition circuit generates a plurality of sparks in each cylinder each combustion cycle from the single ignition capacitor device when a fuel charge injected into the cylinder is stratified.
  • 4. An internal combustion engine comprising:a plurality of cylinders; a spark plug in each cylinder of the engine, to produce ignition sparks in each cylinder; a voltage source; and an ignition circuit electrically coupled to the voltage source and to each spark plug, wherein the ignition circuit is operable to produce a plurality of ignition sparks in each spark plug each combustion cycle from the single ignition capacitor device, comprising: an electronic control unit for generating ignition control signals; a pulse width modulator that produces output pulses of varying pulse width in response to ignition control signals; an electronic switch; a transformer having a primary winding and a secondary winding; the primary winding being electrically coupled to the pulse width modulator and the electronic switch for generating a flyback voltage in the primary winding that is coupled to the secondary winding.
  • 5. An internal combustion engine comprising:an engine block defining at least one cylinder for receiving a fuel charge therein; a spark plug mounted in the engine block and communicating with the at least one cylinder; a voltage source; an ignition circuit electrically coupled to each spark plug, wherein the ignition circuit is operable to produce a plurality of ignition sparks in each spark plug each combustion cycle, the ignition circuit being adapted to generate a greater number of sparks during each combustion cycle when a fuel charge in the cylinder is stratified than when the fuel charge in the cylinder is homogeneous, the ignition circuit comprising: an electronic unit for generating ignition control signals; a pulse width modulator electrically coupled to the electronic control unit, wherein the pulse width modulator produces an oscillating output in response to the ignition control signals; a transformer; a ignition capacitor device; means for electrically coupling the transformer to the voltage source and to the pulse width modulator to generate a flyback voltage to charge the ignition capacitor device; and means for electrically coupling the ignition capacitor device to each of the spark plugs.
  • 6. The internal combustion engine as recited in claim 5, wherein the means for electrically coupling the transformer to the voltage source and to the pulse width modulator to generate a flyback voltage to charge the ignition capacitor includes a bank of insulated gate bipolar transistors electrically connected in parallel, each transistor having a gate, a drain and a source.
  • 7. The internal combustion engine as recited in claim 6, wherein each gate is electrically coupled to the pulsed output of the pulse width modulator, each drain is electrically coupled to the primary winding of the transformer, and each source is electrically coupled to ground and to the input of the pulse width modulator.
  • 8. The internal combustion engine as recited in claim 5, wherein the means for electrically coupling the single ignition capacitor device to each of the spark plugs includes an ignition trigger circuit that selectively operates in response to an ignition control signal to enable a discharge path for the single ignition capacitor device.
  • 9. The internal combustion engine as recited in claim 8, wherein the discharge path for the ignition capacitor includes a silicon controlled rectifier that is operated in response to ignition control signals.
CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of copending International Application Serial No. PCT/US97/10206, filed Jun. 19, 1997 claiming the benefit of U.S. Provisional Application Ser. No. 60/020,033, filed Jun. 21, 1996.

US Referenced Citations (3)
Number Name Date Kind
5183024 Morita et al. Feb 1993
5429103 Rich Jul 1995
5471362 Gowan Nov 1995
Provisional Applications (1)
Number Date Country
60/020033 Jun 1996 US
Continuations (1)
Number Date Country
Parent PCT/US97/10206 Jun 1997 US
Child 09/201363 US