you are not lighting the fuel with a torch are you though. Nor a match. It is a controlled burn in a high pressure environment that happens very quickly. If you have a weak spark, you will not be able to burn as much fuel as a stronger spark would in the same amount of time. I am not even sure how you can argue this and it is a proven fact.
Correct. There
are many factors that determine combustion efficiency, and spark power
and duration are one of these factors. One thing that is very often overlooked, though, is the faster the combustion, the more energy is extracted.
Modern cars tout a 99.9% burning of the fuel that goes into them. That is true (because they count burning in the catalytic converter
). But the gasoline engine is still only 25-30% efficient because not all of that burning is doing usable work. The faster the fuel is burned, the more work goes to the piston and the less is wasted as heat. Better spark characteristics help more quickly initiate combustion and more efficiently burn the fuel.
I agree that if the spark is below what's required you won't get proper combustion, but if it's above what's required I don't think it's proven that more spark will burn more fuel.
If more spark would burn more fuel, then why not have bigger ignition systems instead of catalytic converters?
Because catalytic converters are mandated by law.
And the EPA requires automotive manufacturers to maintain emissions guidelines to 100,000 miles which means 100,000 mile plugs. They start with a small gap so that at 100,000 miles when the gap is huge due to spark erosion they'll still fire.
Well holden, it is possible. You are doubling the resistance by pairing up a resistor cab and plug so it will require more energy to make the jump.
Crush, the ignition system on these bikes is not that strong. I think somewhere around 14-18,000 volts and that's all. Now when you add to it that the years prior to 77 run rich already, there is no way all the fuel is being burned in that short of time. Think if it this way, your engine has something like .05 seconds to burn fuel at idle, a stronger spark will allow that mix to burn faster. As you raise rpm, you reduce the amount of time available for burning.
You are correct in that it may effect the spark by running both sets of resistors (in the plug and in the cap). BUT your explanation is only slightly correct.
The resistance in the plugs, wires, and caps, has very little to do with the voltage required to initiate the spark.
Think of a simple battery/resistor circuit (see attachment). If you were to measure the voltage across the open circuit in the attached diagram, it will be
exactly the same voltage as is available from the battery. No matter if the resistance value is 1 ohm or 1M ohm, the voltage is still the same with no drop across the resistors.
The voltage is what initiates the spark.
Also, while the factory ignitions may be
capable of producing 14,000 volts, they aren't actually required to. The plug gap, electrode temperature, shape, and metal composition, and conditions inside the cylinder is what determines the voltage requirements. At modest gaps and modest pressures (inside a stock SOHC4) the voltage requirement to initiate the spark event is closer to 5,000 volts. Widen the gap or increase the pressure, and the voltage requirement increases.
The in-line resistance reduces the peak spark
current and increases the spark
duration.
The current is reduced because that's what resistors do.
The duration is increased because the voltage from the coil doesn't drop down to zero instantly. Due to the nature of inductance, once current begins to flow through the spark gap, it wants to continue to flow until the coil runs out of energy. Basically, the coils store current. If the flow of current is reduced, it takes longer to drain it all (compare a bucket full of water draining through a small hole [high resistance] to a bucket full of water with the bottom blown off [dead short]).
Remember, though, that the coils only store so much total energy (combination of voltage and current) so you don't want
huge resistances in-line with the plug. Now whether the resistive plug combined with the resistive cap is too much, that has yet to be determined and testing will have to be done to find out.
