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Upon further review - yup, still horse puckey Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 10 Mar 2008 04:44:02
In Reply to: Pulstar - $ 23.95, Saabnutt, Sat, 8 Mar 2008 19:53:44 Members do not see ads below this line. - Help Keep This Site Online - Signup |
That's not a press explanation, that's the output of a rather poor buzzword generator.
Here's the biggie - "more reserve electrical power". A spark plug does not store or amplify energy power. There is no physical means to do so. The spark plug can only pass on as much energy as the ignition system provides it, with the exact timing the ignition system provides. A spark plug is basically a wire.
The next part talks about needing to advance the timing with increase in engine speed. Yup, cars have been doing that automatically since they stopped putting Spark Advance levers on the steering wheel. In the old days it was called a distributor; today it's a basic part of the Saab Trionic system, and every other car on the road that doesn't have a crank start.
Yes, how the flame front moves from the plug is critical to power. The original CVCC did indeed have a pre-ignition chamber, which allowed a slightly richer mixture to start burning, and then ignite a leaner mixture in the main part of the cylinder head. This allowed the use of a leaner mixture without knock, and better fuel economy. If you'll notice, they don't make engines like that anymore because the technology has moved past it. It required a complex head design and multiple valves.
Yes, there are multi-plug designs (Alfas are famous for them). But the cylinder head is designed for it, and the second plug is now a necessary evil. Just throwing in a 'super duper' spark plug is not going to change the cylinder head design. You can't simulate the CVCC head design with a fancy spark plug.
Multi-prong spark plugs have been around for a while, and they serve a useful purpose - they are more resistant to fouling. That's because there are more surfaces where the spark can jump from. As Saabnutt points out, a spark will jump from only one place - once the plasma arc has been established, that becomes the low resistance path. I use multi-prong spark plugs in my two-stroke, because when cold, the oil in the gas tends to foul the plugs. If one of the prongs is oil-fouled, hopefully at least one of the others isn't. A spark will jump, and once the mixture gets near right, the combustion in the chamber will clean the gunk off the other prongs.
In modern engines, plug fouling is very, very rare, and the sign of a seriously screwed up engine.
Bottom line - spark plugs do not store energy. They do not amplify power. No matter how many prongs, they aren't going to cause an improvement in the flame propagation - that is set by the cylinder head design. Yes, the wrong spark plug can mess that up, but once the spark plug provides the spark it was designed for, its job is over.
And the final sniff test - if a car company could get an improvement in power and economy with a spark plug, instead of, say, expensive cylinder head designs, turbochargers, variable intake rails, variable valve timing, adjustable displacement, etc., wouldn't it seem reasonable that they would try it? What (valid) reason would they have not to incorporate them into their cars? Somebody at GM/Ford/Chrysler/Tata must read SA.
posted by 192.249....
, Mon, 10 Mar 2008 04:44:02 <-- Viewing This Message
, Mon, 10 Mar 2008 08:47:47, Sat, 8 Mar 2008 17:01:47, Sun, 9 Mar 2008 11:05:47, Mon, 10 Mar 2008 13:26:04
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