FUELLESS CAR PROTOTYPE by ISMAEL MOTOR

[Magluvin]

Hi guys.
Is this discussion about a well known principle used in the auto ignition system? Here is a picture from well known book which describes many such aspects; what about a term "inrush current"? It's "Practical Transformer Handbook". See attachment.

If you read the description in the pic you posted, it says the capacitor is to protect the switch contacts. But it doesnt just do that. If you try this setup on the bench, you will quickly find out that the capacitor helps to give a much better spark. When that switch is released( without the cap in place) you will see a spark across the gap of the switch.

But when you have the cap across the switch, that voltage has a path into the cap instead of the open contacts of the switch.  So now what happens? Oscillation!  ;] And a nice fat spark. Not just 1 puny static cling looking and sounding spark as with no condenser(cap) across the switch.

But most books on this will only say it is to protect the switch. ;] 

Mags

[Magluvin]

An IRFZ44 D to S is .028 ohms on resistance.  A very common mosfet



Mags

I would need 5 or 6 of them in parallel to come close to my theoretical switch in my circuit above. I wasnt being unrealistic.  ;]

Mags

[Qwert]

 Sorry, Magluvin, I meant something else: "sudden collapsing current". Here is a quote from the mentioned book. The picture in my previous post relates to this quote:

Stepped-up high voltage from not so high turns ratio.

An experimenter is interested in determining the approximate turns ratio of an automobile ignition coil. He impresses a small audio frequency sinewave on the primary terminals and uses an oscilloscope to measure the induced voltage in the secondary. As a result of this measurement technique, it is found that the voltage step-up is approximately 100. This does not appear reasonable because 100 times the 12 V of the automobile battery falls far short of the 15 000-30 000 V needed for firing spark plugs. What is the nature of the discrepancy? Although not commonly referred to as a 'flyback' transformer, the ignition coil develops its high secondary voltage in a similar manner to the flyback transformer in a television set. In both instances, the primary winding requires a waveform with a very high rate of voltage or current change. Such a waveform induces a high voltage counter EMF in the primary and it is this induced voltage which is stepped-up further in the secondary. Thus in an automobile ignition system, the abrupt cut-off of the applied 12 V induces a counter EMF in the primary with a peak amplitude of about 250-300 V. When this purposely-produced 'transient' is multiplied by a 100 to 1step-up turns ratio, one obtains the 25 kV or so needed for reliable firing ofthe plugs. The basic breaker point ignition system is shown in Fig. 5.2

[konehead]

Hi Magluvin
you are "supposed to" not have a resitance like your 99 ohms or 10 ohms in the circuit, UNTIL the caps fill up first - to whatever voltage you desire them to be at (via pulse width of short, frequency of shorts, cap size and all the variables that decide how fast those caps fill up in unloaded-condition)....THEN have a Noff SWon disconnect the coils being shorted from that capacitor being filled up, WHILE at same time, a Noff SWon swtihc connects caps to your load....this way the coils being nver shorted never "see" the load itself - only the resistance of the cap itself is all the coils being shorted have to worry about resistance-wise....can you do this with your simulator program?
when you have a lump resistive load across that cap, you are snubbing away alot of potential power and also will be causing a refleciton back to the primary, so you get extra draw when coils fill up which is no good and is what you want to avoid always....
when yo uget to building the real thing, for sure try 5 mosfets or so in paralell, amd/or very high amp low resistance mosfets that are also HV.....try some IRF P460 NPN types .... remember to put a pull-down 1K resistor across the whole cluster of mosfets if you paralell them - I like to also put a 1K pull-down resistor across EACH mosfet as well as one all the way across the cluster to make sure those mosfets never stick-on...also you should use a driver chip too - I like the 4421 type, and if you pop in a 4422 instead, it inverts the mosfet swithces to become Noff SWon instead of Non SWoff (or vice versa) so this is really easy way to make a "two-stage" output switching circuit...
If you want to have continuous short, then the way to go for that is the Thane method of a certain  high frequency and high ohm coils (IF somethign rotating), to get speed up under load, or the RomeroUK magnets behind cores method to get speed up under load...(again if somethign rotating)..if non-rotating, best to fill up caps unloaded with peak-short, dump caps to load when caps are disconnected from coils...
that "lump" resistive load is how they hide OU !!

[Qwert]

Oops! It looks like you gouys are convinced that the distributors' role is only one in ICE ignition system: to distribute power. My above two posts prove it has also another task: to reinforce the power.