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Old 05-29-2008, 06:38 AM   #11
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Are these people that say these things going mostly off of theory and not in practice like we all do?
Well, this thread has a lot of theory in it, and fumesucker's last post explains the theory behind P&G pretty well I think. However, I can't argue with results. P&G provided significant gains for me. On my next tank I have to try combining it with my previous best strategy, which was skipping 3rd gear.

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Also has anybody considered using a stirling engine to power a compressor for an airconditioner? That air conditioner would cool the engine coolant and then the engine could allow for hotter temperatures and so on? Can you reduce NOX by reducing the temps of the coolant?
Consensus here seems to be that more heat == more FE. However, if you could sink the heat away without using the fan, you could save the energy spent operating the fan.

There have been a couple new threads in the past couple days suggesting harvesting waste heat from the exhaust, but not much talk about getting it from the radiator.
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Old 06-10-2008, 03:38 AM   #12
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Originally Posted by theholycow View Post
Well, this thread has a lot of theory in it, and fumesucker's last post explains the theory behind P&G pretty well I think. However, I can't argue with results. P&G provided significant gains for me. On my next tank I have to try combining it with my previous best strategy, which was skipping 3rd gear.



Consensus here seems to be that more heat == more FE. However, if you could sink the heat away without using the fan, you could save the energy spent operating the fan.

There have been a couple new threads in the past couple days suggesting harvesting waste heat from the exhaust, but not much talk about getting it from the radiator.
Actually I meant that you would take the exhaust heat, power stirling engine which powers air conditioner, then run coolant through the "cold" part of the radiator for the air conditioner. Basically you'd be super cooling down the coolant in the engine.
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Old 06-10-2008, 04:22 AM   #13
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If you were to use an exhaust heat powered stirling engine the best use would be to power the accessories, including cabin AC..

Cooling the radiator that way would be a complete waste, radiators are not very expensive and if you want more cooling just put in a bigger radiator.
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Old 06-10-2008, 07:29 AM   #14
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Originally Posted by ************* View Post
Actually I meant that you would take the exhaust heat, power stirling engine which powers air conditioner, then run coolant through the "cold" part of the radiator for the air conditioner. Basically you'd be super cooling down the coolant in the engine.
Actually, that reminded me of another piece of technology that could get involved. How about ammonia absorption cooling?

http://en.wikipedia.org/wiki/Absorption_refrigerator

That way, you could use the heat more directly to cool the cabin air.
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Old 06-19-2008, 12:25 AM   #15
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If you were to use an exhaust heat powered stirling engine the best use would be to power the accessories, including cabin AC..

Cooling the radiator that way would be a complete waste, radiators are not very expensive and if you want more cooling just put in a bigger radiator.
It's not that radiators are expensive, if anything using a radiator is more cost effective than a stirling engine if you want to have the same cooling performance. The idea would be to one save weight, two have super good cooling performance of the engine which would lead to three, having more aggressive timing since knock would be less likely.
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Old 06-19-2008, 04:40 AM   #16
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Diesels operate by welcoming and inviting detonation. COMPLETELY different.
Some of the engines have a special area offset of the main cylinder to start preignition. Forgot its name I've been out of school and out of the industry. Indirect ignition is what i think it is
Diesels operate at 1:1 or 20:1 a/f ratio. Your foot regulates the fuel going in, which will always ignite and push piston. The fuel ignites because of the pressure and heat already there, no spark. More fuel more power no matter what. When there is an oil leak and it gets into the cylinder you can have a runaway engine that revs and revs itself to death. Locomotives do this and id not want to be anywhere near that. The gas engine you are operating an air plate, that the computer injects fuel to hit that 14.7:1 stoich nonsense.

Gas engines that are turboed are always on the brink of detonation. Hot air is the last thing a turbocharged gas engine wants. The turbine already does a great job heating the air--enough to need air to air intercoolers. In the mid 1980s ford turbocharged the pinto 2.3 engine. It ended up in the mustang GT, a special thunderbird turbocoupe and the merKur xr4ti. I have a merkur. It came with no intercooler, which meant all the hot air went straight into the engine. All it did was not let me tune past 13psi. If I had a bad tank of gas I was lucky to keep up with a 10:1 compression engine of the same displacement. The ECU of all turbocharged cars are very conservative on the ignition timing so they wont blow up with the introduction of more air. If you start doing sensor manipulation with your car you will find your mpg's come up when you can KEEP as much timing as possible. Bump your timing add some water injection and you will have power AND economy. With an intercooler, you can crank on the boost and add timing past what the fuel injectors can deliver.
Anyway the economy of that ford 2.3 engine was no better than the N/A counterpart used in the ford ranger and mustang. The power in stock form was almost as nice as the 5.0 v8 engine, but the mpg's werent double like you want to see. Another example is my other car, the dodge srt-4 old epa 22/30. There is no neon 2.4L but in the PT cruiser its better than the turboed one, but advertized as the same. I would rather see you convert to propane and turbocharge that, as propane is a gas when introduced so there are no "hot spots" and the effective octane rivals racing gasoline so when set up right it should be safe for the engine.

I just reread your post before hitting submit. (lightbulb) CVT transmission on the 2006 altima 2.5 rental I had ...steady 4500rpm when you mash gas and it holds it there as you accelerate. When you are part throttle and behaving its constantly hunting for sweet spot(s) depending on the terrain.
Sounds like setting the cruise at exactly 40 mph in my old Pontiac, and in my Buick before I upgraded the tranny. (Both had TH 350 transmissions). At 40 on a flat, smooth road the tranny didn't know if it wanted to be in second, third, or lock the torque converter. It would constantly hunt & seek until you either sped up or slowed down 1 mph.
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