U.S. patent number 3,593,696 [Application Number 04/787,324] was granted by the patent office on 1971-07-20 for electronic ignition system for producing high frequency spark trains for internal combustion engines.
This patent grant is currently assigned to Consiglio Nazionale Delle Ricerche-(C.N.R.). Invention is credited to Angelo Raffaele Guido.
United States Patent |
3,593,696 |
Guido |
July 20, 1971 |
ELECTRONIC IGNITION SYSTEM FOR PRODUCING HIGH FREQUENCY SPARK
TRAINS FOR INTERNAL COMBUSTION ENGINES
Abstract
An electronic ignition system for internal combustion engines is
disclosed, the ignition system comprising circuit means controlled
in synchronism with the engine for producing a high frequency spark
train capable of ensuring a perfect ignition of the mixture into
each cylinder of the engine.
Inventors: |
Guido; Angelo Raffaele (Naples,
IT) |
Assignee: |
Consiglio Nazionale Delle
Ricerche-(C.N.R.) (Rome, IT)
|
Family
ID: |
11241149 |
Appl.
No.: |
04/787,324 |
Filed: |
December 27, 1968 |
Foreign Application Priority Data
|
|
|
|
|
Feb 29, 1968 [IT] |
|
|
35171/68 |
|
Current U.S.
Class: |
123/607;
315/209R |
Current CPC
Class: |
F02P
15/10 (20130101) |
Current International
Class: |
F02P
15/00 (20060101); F02P 15/10 (20060101); F02p
003/02 () |
Field of
Search: |
;123/148E,149,146.5A
;315/209,29T |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Goodridge; Laurence M.
Claims
I claim:
1. An electronic ignition system for internal combustion engines,
said ignition system comprising circuit means controlled in
synchronism with the engine for providing sparks at the spark
plugs, said circuit means producing a high frequency spark train
capable of insuring a perfect ignition of the mixture into each
cylinder of the engine, said circuit means comprising a plurality
of electronic circuits including a first amplification stage means
for providing a series of control signals in synchronism with the
engine, differentiating circuit means for shaping said control
signals, a multivibrator means for producing square waves in
response to said shape control signals, a second amplification
stage means for amplifying said square waves to provide a power
source, and a final oscillator means powered by said second
amplification stage means providing a power source and triggered in
response to each amplified square wave to produce trains of spark
pulses, each train having a time period equal to the duration of
said square waves.
2. An electronic ignition system as defined in claim 1, further
including a rotatable member driven by the engine rotating at a
predetermined speed, said rotatable member including teeth
projecting outwardly from the periphery thereof, an electromagnetic
sensing device, said rotatable member being positioned so as to
face said electromagnetic sensing device, said electromagnetic
sensing device being adapted to produce signals applied to said
first amplification stage means under the control of said outwardly
projecting teeth; said rotatable member and said electromagnetic
sensing device being provided at the input of said set of
electronic circuits, and a transformer means provided at the output
of said set of electronic circuits for increasing the voltage of
said oscillations from said modulated final oscillator means to a
high level, rotary distributor means rotating at predetermined
speed and coupled with said transformer means for distributing the
high voltage oscillations through conductors to the ignition spark
plugs.
3. An electronic ignition system as defined in claim 2, further
including battery means for energizing said set of electronic
circuits.
Description
The present invention generally relates to ignition systems and
particularly concerns an electronic ignition system for internal
combustion engines, that is able to produce, by the use of spark
plugs of conventional type, a train of sparks instead of a single
spark as is normally provided either by conventional ignition
systems or by transistorized ignition systems.
In accordance with the subject invention, such a train of sparks is
produced by employing an electronic device, a block diagram of
which is shown in the accompanying drawing depicting a preferred
operative embodiment.
Referring now in detail to the drawing, numeral 1 generally
designates a disc connected with a rotary shaft 2 driven by the
engine. From the peripheral edge of disc 1, symmetrically placed
teeth 3 project outwardly, the number of the teeth being the same
as that of the cylinders of the engine.
Near disc 1 is located an electromagnetic sensing device 4 adapted
to produce signals every time a tooth passes in front of it, the
signals being then applied to an amplifier 5. The signals, which
are duly amplified in amplifier 5 are then applied to a
differentiating circuit 6, where the signals are shaped and peaked
so as to provide control pulses for a multivibrator 7.
As is well known, multivibrator 7 produces square waves in response
to the control pulses. The square waves are then amplified by an
additional amplifier 8 and cause starting of the operation of an
oscillator 9, which produces oscillations for a time period equal
to the duration of the square waves.
The oscillations which are generated by the oscillator 9 comprise a
pulse train and are then fed to a transformer 10 which increases
the voltage to the necessary high level, the oscillation than being
fed to conductors 12 of the spark plugs (not shown in the drawing)
by means of a distributor 11 which rotates in synchronism with the
rotary movement of the disc 1 and which is driven, in turn, by the
engine.
In response to each pulse of the pulse train sent by the oscillator
9, a spark is produced by the spark plugs; so that at the spark
plugs, a real train of sparks exists, the duration of which is
determined by the duration of the square pulses at the output of
the multivibrator 7.
Having the above structure and operation now in mind, it will be
apparent that, by employing the system of the invention, the
ignition of the mixture in the engine cylinder is no longer
obtained by means of a single spark, but, on the contrary, by means
of a train of sparks at a very high frequency.
Experiments carried out by employing the ignition system of the
invention has proved that the sparks of the train, which follow one
another with very high frequencies of 80 kHz. to 150 kHz., for
example insure the ignition of even weak mixtures, which, on the
contrary, could be not ignited by utilizing conventional ignition
systems. Moreover, as compared with the conventional ignition
systems and with the same mixture strength, the system of the
invention enables the achievement of a more perfect combustion,
which results in the reduction of air pollution, as well as in the
increase of the thermal efficiency of the engine.
Another advantage of the aforesaid system consists in the fact that
the contact breaker provided in the conventional ignition systems
is no longer necessary. As a result of the elimination of the
breaker device, a greater reliability of operation can be obtained,
since overhauling or periodical replacement of the contacts becomes
unnecessary, these maintenance operations being those which
frequently cause interruptions of engine operation.
The electronic circuit of the inventive ignition system is
energized from the usual battery which is a part of the equipment
of the motor vehicle.
It will be apparent that the system described and illustrated in
the accompanying drawing should be considered as comprising an
exemplary inventive embodiment and not as limiting the scope of the
invention as the constituent components of the device of the
invention as described could be replaced by other similar
components which are operatively equivalent, either from a
mechanical point of view or from an electronic one, without
departing from the scope of the invention as sought to be defined
in the following claims.
* * * * *