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I used to work for a spark plug maker, of course a spark plugs could improve combustion if placed right... but a lot has to do with fighting for space with 4 valves and overhead cams. Plus, a double fine wire projected tip 8mm plug is about the edge of what can be made and even...
The "calibrated plumbing" is to time the exhaust pressure pulse to hit the intake runner at nearly the same time the valve opens (this application is a constant RPM engine).
The mechanical controlled EGR based on throttle position is probably the cheapest and easiest to employ. For this 6-mode...
Thank you Franz,
You mentioned you had exhaust flowing above the throttle body, did you try going behind the throttle plate (where more benefits could be attained).
Currently I am working on a gasoline 6HP single. What I have noticed so far is that WOT power drops 5-10%. At all load points HC...
I am working on air-cooled single and twin cylinder engines. As of next year, our friends at CARB tighten the regulations on these smaller engines such that a catalyst is needed (for a reduction of about 38% HC+NOx).
I have tested catalysts and they will all work just fine, at the cost of...
I know NGK/NTK has been making them for years. I believe for an VW application (although I don't know if it's in the US).
But you can call them up via their website and see if they would sell you one or two for a crazy amount of $$$. I don't know what Siemens has, but they aren't going to...
You can't just go "Yellow" as GM totes on it's ads without other concerns. First off, E85 is not available everywhere. Secondly, small engines cannot afford a 40% reduction in power and economy and just expect Joe Consumer to buy into that (small engines use a much higher percentage of their...
In the EPA's study, they looked at check-valves that would let a little air in the exhaust due to the pressure pulses from the valves open/closing... but they found they were not needed.
There is enough oxygen still remaining that the cat is beneficial
I know the engine runs rich, all air-cooled do. But the catalysts plan for that and are able to last the 1000hrs of life required.
I am going to lean things out, to see if I can lower HC without raising NOx too much. When those benefits are no longer measurable, then I will have to add some...
Thank you for all the interesting debate.
I know open loop catalysts work, some manufacturers are using them today. The EPA also just did a study on exactly this and found it to work.
The production costs on these engines are like $150-300, adding a $12 cat-muffler is hard to swallow, plus...
cleverlever,
OHV application. I will take a scan of what's out there on the US patent website.
I am having a difficult time picturing the mechanism in my head, I need more details.
The cold start emissions aren't really the concern for emissions. Emissions that are reported to EPA/CARB are...
I am trying to digest how this would be possible on a single cam, as cheaply as possible.
There is compression release, but it is simply a spring mass system based on RPM.
Please describe in detail how you imagine being possible.
The small engine market is right now on the verge of being where the automotive world was in the mid-70s. Primitive cats, inexpensive EGR, etc.
Variable Valve Timing to incorporate internal EGR is not something the small engine market can afford at this time (although the preferred method)...
The 2006 std is 16.1 g/kWh (HC + NOx) and drops to 10.0 g/kWh for 2007.
I am investigating a open loop catalyst as well, no sensors.
But, I believe EGR would be cheaper and might get us by until more stringent regulations come in 2012...
In regards to the cam timing - we really can afford to...
I am trying to put EGR on a small air-cooled engine as a possible cost-saving alternative to a catalyst in controlling HC and NOx emissions.
Does anybody know some makers of "dumb" (as in no closed-loop control) EGR valves for engines of 500cc and less?
NOx is obvious, but I think HC will go...
