TL's Ignition System (Spark Plug Firing)
08-20-2006, 12:37 AM
#1
Moderator
Thread Starter
TL's Ignition System (Spark Plug Firing)
Have a question for you guys about spark plug "firing" on the TL:
Since the engine does not contain a distributor, do the plugs fire in this manner:
(From www.sparkplugs.com)
If so, why doesn't the TL use Double Platinum Spark Plugs? How would Iridium plugs last 105k if only the center electrode was Iridium and the ground electrode was not of a platinum or similar "upgraded" material? Or does this engine merely fire on the compression stroke (center to ground) only, and not on the exhaust stroke? (to the plugs)
TIA.
Since the engine does not contain a distributor, do the plugs fire in this manner:
DIS (Distributorless Ignition System) fires twice as often as a conventional ignition system and changes direction of fire. A conventional ignition fires on the compression stroke from the center electrode to the ground electrode. A DIS fires on the compression stroke from the center to the ground electrode, it also fires on the exhaust stroke from the ground to the center electrode. As this requires the spark plug to fire twice as often, it necessitated the advent of double platinum spark plugs which have platinum tipped ground and center electrodes.
If so, why doesn't the TL use Double Platinum Spark Plugs? How would Iridium plugs last 105k if only the center electrode was Iridium and the ground electrode was not of a platinum or similar "upgraded" material? Or does this engine merely fire on the compression stroke (center to ground) only, and not on the exhaust stroke? (to the plugs)
TIA.
08-20-2006, 12:41 AM
#2
Moderator
Thread Starter
So, here's what an GM engineer told me, as to why many Iridium plugs do not contain an "upgraded" material for the ground electrode. Could such be the case with the TL's setup?
There isn't an iridium pad on the ground electrode since most all the
ignition systems the iridium plugs are being developed for are not the
direct fire coils with reverse polarity on half the plugs. The coil at
plug or coil near plug systems all fire the plugs with the same polarity so
the precious metal on the ground electrode is less important.
ignition systems the iridium plugs are being developed for are not the
direct fire coils with reverse polarity on half the plugs. The coil at
plug or coil near plug systems all fire the plugs with the same polarity so
the precious metal on the ground electrode is less important.
08-20-2006, 02:53 PM
#3
To make a long story short...
SodaLuvr,
No matter what ANYBODY tells you, copper is far better conductor than platinum or iridium. Here is some education from an article I wrote about the Ford DIS/E-DIS systems (found on the CrownVic.net).
IGNITIONS:
Let me explain the Ford DIS ignition system now. The Ford DIS/E-DIS system works on a waste spark management. One half of the spark plugs fire from the center electrode to the ground electrode and the other half fires from the ground electrode to the center electrode. The EEC fires two spark plugs simultaneously. One spark plug on the compression stroke uses the majority of the coils stored energy, the other spark plug on the exhaust stroke uses very little of the coils stored energy.
The ignition coils contain two separate ignition coils. Each coil is controlled by the ignition control module through two coil leads. Each ignition coil activates two spark plugs simultaneously:
One spark plug on the compression stroke; this spark plug use the majority of the ignition coil stored energy.
One spark plug on the exhaust stroke; this spark plug uses very little of the ignition coil stored energy.
These two spark plugs are connected in series.
The firing voltage of one spark plug will be negative with respect to ground.
The voltage of the other spark plug will be positive with respect to ground.
MATERIAL TYPES:
Materials used for spark plugs can dramatically alter longevity, efficiency, power, and even knock sensitivity. We will discuss three types of materials used today to manufacture spark plugs. The first is Copper, which is becoming more and more expensive.
Copper melts at 1,981 degrees F and that makes it suitable for an internal combustion engine. It’s a great conductor of electricity (second to silver), heat and can resist corrosion to a point. Copper is very soft and can be easily drawn into wires. The majority of the spark plugs on the market today are copper since it is the most economical of the material to use. Nickel is also used as an alloying material for a copper spark plug. However car makers have be using platinum plugs in their engines to increase the tune-up intervals.
Platinum is a precious metal and it is rare, that makes it more expensive than copper. It melts at 3,200 degrees F. and it is highly resistant against corrosion. Platinum has a high fuse point with high electrical resistance. It is also harder than copper, making it very useful for longevity of a spark plug. Make no mistake, copper is a better conductor than platinum.
Finally, we will discuss Iridium. Iridium, is extremely hard and brittle material and extremely rare as well. The melting point is 7,466 degrees F. and it is considered the densest of elements. Iridium is used solely as an alloying material for platinum. Platinum alloys contains a small amount of iridium which is much harder than pure platinum.
Keep in mind the platinum and iridium plugs are only tipped or coated. The core is still copper and will remain this way.
HEAT RANGES:
Heat ranges of a spark plug are often misunderstood and neglected. The term heat range refers to the relative temperature of the core nose of the spark plug. “Hot” and “cold” terms refer to the thermal characteristics of the spark plug or the ability for the spark plug to remove heat from its firing tip and combustion chamber.
A cold spark plug transfers heat faster from its firing tip into the insulator. This is due to the shorter insulator nose it has. That helps keep the tip of the plug from glowing red and accidentally pre-igniting the air/fuel mixture. The heat is transferred into the cylinder head and engine coolant.
A cold plug is used on high compression engines or extremely high cylinder pressure situations (i.e. superchargers, nitrous, or turbochargers). A hot spark plug transfers heat from its firing tip, slowly. The hot spark plug is used in a low compression engine to avoid fouling since the combustion chamber temperatures are low.
It is important to remember that a spark plug does not create heat; it simply removes it acting as a heat exchanger. The way the spark plug companies control heat ranges is to normally vary the length of the core nose or the alloy of the material used in the electrodes. So a hotter plug will have a longer insulator nose and therefore a long heat transfer path. Cold spark plugs have a short insulator nose and can transfer heat much faster. A cold plug reduces the chances of knock, making the engine less knock constrained.
The trade off is fouling. A colder spark plug is prone to fouling faster than a hotter one. Let me explain why. A spark plug must reach a certain temperature for it to burn off any carbon in the combustion chambers. Also the same applies to fuel. If the plug is to cold, it may not reach its cleaning temperature during normal driving and that will cause the plug to accumulate deposits.
If the deposits aren’t burned off, the chance for a misfire or when the air/fuel mixture is not ignited properly or at all can occur. Since a hot plug retains more heat before transferring it to the engines cooling system, it can burn off these deposits more efficiently.
Likewise, if a spark plug is subjected to extreme temperatures that exceed 1,000 degrees C., the spark plug can blister and sometimes melt. Just so we are clear, the heat range of the spark plug has no effect over voltage or resistance required to jump the gap. The hotter the spark plug (heat range), the more efficient it will be and the hotter the burn will be.
I hope this helps,
A-Train
No matter what ANYBODY tells you, copper is far better conductor than platinum or iridium. Here is some education from an article I wrote about the Ford DIS/E-DIS systems (found on the CrownVic.net).
IGNITIONS:
Let me explain the Ford DIS ignition system now. The Ford DIS/E-DIS system works on a waste spark management. One half of the spark plugs fire from the center electrode to the ground electrode and the other half fires from the ground electrode to the center electrode. The EEC fires two spark plugs simultaneously. One spark plug on the compression stroke uses the majority of the coils stored energy, the other spark plug on the exhaust stroke uses very little of the coils stored energy.
The ignition coils contain two separate ignition coils. Each coil is controlled by the ignition control module through two coil leads. Each ignition coil activates two spark plugs simultaneously:
One spark plug on the compression stroke; this spark plug use the majority of the ignition coil stored energy.
One spark plug on the exhaust stroke; this spark plug uses very little of the ignition coil stored energy.
These two spark plugs are connected in series.
The firing voltage of one spark plug will be negative with respect to ground.
The voltage of the other spark plug will be positive with respect to ground.
MATERIAL TYPES:
Materials used for spark plugs can dramatically alter longevity, efficiency, power, and even knock sensitivity. We will discuss three types of materials used today to manufacture spark plugs. The first is Copper, which is becoming more and more expensive.
Copper melts at 1,981 degrees F and that makes it suitable for an internal combustion engine. It’s a great conductor of electricity (second to silver), heat and can resist corrosion to a point. Copper is very soft and can be easily drawn into wires. The majority of the spark plugs on the market today are copper since it is the most economical of the material to use. Nickel is also used as an alloying material for a copper spark plug. However car makers have be using platinum plugs in their engines to increase the tune-up intervals.
Platinum is a precious metal and it is rare, that makes it more expensive than copper. It melts at 3,200 degrees F. and it is highly resistant against corrosion. Platinum has a high fuse point with high electrical resistance. It is also harder than copper, making it very useful for longevity of a spark plug. Make no mistake, copper is a better conductor than platinum.
Finally, we will discuss Iridium. Iridium, is extremely hard and brittle material and extremely rare as well. The melting point is 7,466 degrees F. and it is considered the densest of elements. Iridium is used solely as an alloying material for platinum. Platinum alloys contains a small amount of iridium which is much harder than pure platinum.
Keep in mind the platinum and iridium plugs are only tipped or coated. The core is still copper and will remain this way.
HEAT RANGES:
Heat ranges of a spark plug are often misunderstood and neglected. The term heat range refers to the relative temperature of the core nose of the spark plug. “Hot” and “cold” terms refer to the thermal characteristics of the spark plug or the ability for the spark plug to remove heat from its firing tip and combustion chamber.
A cold spark plug transfers heat faster from its firing tip into the insulator. This is due to the shorter insulator nose it has. That helps keep the tip of the plug from glowing red and accidentally pre-igniting the air/fuel mixture. The heat is transferred into the cylinder head and engine coolant.
A cold plug is used on high compression engines or extremely high cylinder pressure situations (i.e. superchargers, nitrous, or turbochargers). A hot spark plug transfers heat from its firing tip, slowly. The hot spark plug is used in a low compression engine to avoid fouling since the combustion chamber temperatures are low.
It is important to remember that a spark plug does not create heat; it simply removes it acting as a heat exchanger. The way the spark plug companies control heat ranges is to normally vary the length of the core nose or the alloy of the material used in the electrodes. So a hotter plug will have a longer insulator nose and therefore a long heat transfer path. Cold spark plugs have a short insulator nose and can transfer heat much faster. A cold plug reduces the chances of knock, making the engine less knock constrained.
The trade off is fouling. A colder spark plug is prone to fouling faster than a hotter one. Let me explain why. A spark plug must reach a certain temperature for it to burn off any carbon in the combustion chambers. Also the same applies to fuel. If the plug is to cold, it may not reach its cleaning temperature during normal driving and that will cause the plug to accumulate deposits.
If the deposits aren’t burned off, the chance for a misfire or when the air/fuel mixture is not ignited properly or at all can occur. Since a hot plug retains more heat before transferring it to the engines cooling system, it can burn off these deposits more efficiently.
Likewise, if a spark plug is subjected to extreme temperatures that exceed 1,000 degrees C., the spark plug can blister and sometimes melt. Just so we are clear, the heat range of the spark plug has no effect over voltage or resistance required to jump the gap. The hotter the spark plug (heat range), the more efficient it will be and the hotter the burn will be.
I hope this helps,
A-Train
08-20-2006, 06:18 PM
#4
Moderator
Thread Starter
Originally Posted by Atrain
SodaLuvr,
No matter what ANYBODY tells you, copper is far better conductor than platinum or iridium. Here is some education from an article I wrote about the Ford DIS/E-DIS systems (found on the CrownVic.net).
IGNITIONS:
Let me explain the Ford DIS ignition system now. The Ford DIS/E-DIS system works on a waste spark management. One half of the spark plugs fire from the center electrode to the ground electrode and the other half fires from the ground electrode to the center electrode. The EEC fires two spark plugs simultaneously. One spark plug on the compression stroke uses the majority of the coils stored energy, the other spark plug on the exhaust stroke uses very little of the coils stored energy.
The ignition coils contain two separate ignition coils. Each coil is controlled by the ignition control module through two coil leads. Each ignition coil activates two spark plugs simultaneously:
One spark plug on the compression stroke; this spark plug use the majority of the ignition coil stored energy.
One spark plug on the exhaust stroke; this spark plug uses very little of the ignition coil stored energy.
These two spark plugs are connected in series.
The firing voltage of one spark plug will be negative with respect to ground.
The voltage of the other spark plug will be positive with respect to ground.
No matter what ANYBODY tells you, copper is far better conductor than platinum or iridium. Here is some education from an article I wrote about the Ford DIS/E-DIS systems (found on the CrownVic.net).
IGNITIONS:
Let me explain the Ford DIS ignition system now. The Ford DIS/E-DIS system works on a waste spark management. One half of the spark plugs fire from the center electrode to the ground electrode and the other half fires from the ground electrode to the center electrode. The EEC fires two spark plugs simultaneously. One spark plug on the compression stroke uses the majority of the coils stored energy, the other spark plug on the exhaust stroke uses very little of the coils stored energy.
The ignition coils contain two separate ignition coils. Each coil is controlled by the ignition control module through two coil leads. Each ignition coil activates two spark plugs simultaneously:
One spark plug on the compression stroke; this spark plug use the majority of the ignition coil stored energy.
One spark plug on the exhaust stroke; this spark plug uses very little of the ignition coil stored energy.
These two spark plugs are connected in series.
The firing voltage of one spark plug will be negative with respect to ground.
The voltage of the other spark plug will be positive with respect to ground.
The description you posted is good...it explains why half of Ford's plugs would contain a plat. pad on the ground and half would have a plat center, whereas, the other half does not (and vice-versa). Cheap asses. They could've used Double Plat. plugs for all of them but chose not to for cost reasons, AFAIK.
So I went ahead and checked the NGK Laser Iridium plugs, which are OE for many Honda/Acura vehicles. They're actually of a Iridium center w/the Plat. Ground for maximum durability in these DIS systems (if such is the case)....$10/plug, not bad, not bad at all...
08-20-2006, 06:52 PM
#6
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The TL only fires on compression. Engines that fire twice have two sparkplug wires hooked to each coil so the engine only needs half as many coils. It is a good way for a manufacturer to save money. The TL uses six coils; one per cylinder.
09-16-2006, 01:16 PM
#7
right, that is the difference between distributorless ignition systems or wasted spark type ignitions (DIS) and Coil on Plug such as the TL. I like the coil on plug, no wasted sparks, coils rarely fail, and best of all, no spark plug wires to mess with
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