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#46
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That's a fair summary. If I was smart enough to have all these solutions I would be out shopping for my own island instead of hanging out with you guys.
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1989 300 SEL that mostly works, but needs TLC |
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Never claimed to be an expert.
And at the end of an 18 hour day I'm bound to make mistakes.I've got plenty of experience as a professional mechanic,and have studdied what materials I could find on related sciences like metalurgy and thermodynamics.And like I said,from all I've seen and read I agree with the basic laws involved.But one indevidual here(not you Craig,You've been more then civil enough) basicly calls me an inexperienced fool because he disagrees with me.Wasted motion can't be changed much in currant engine designs.And thermal efficiency increases of any appreciable ammount are not cost effective.To the best of my knowledge the 98% efficiency in burning the fuel is after the catalytic converter.Not in the combustion chamber.I rode in his truck several times with one pint of fuel being gravity fed to the carburator.We went just over 20 miles each time in city driving.And you'r absoultly correct about wankel engines being more efficient due to fewer moving parts and less parasitic power loss.The outer edge of the rotor uses a spring loaded scraper which acts like a piston ring to maintain the fuel air mixture in each chamber section.The problem with the engines design though is the blowby which occurs past the ends of the rotor.If someone can devise a way to better seal the chambers,I believe the engine would then come into more wide spread use.The reason fuel injected engines get better fuel mileage then comercial carburator designs is due to the high pressures in the injection system.The fuel enters the combustion chamber as a very fine mist,which burns more readily then the droplets common in a carburated engine.A direct injection engine(gas or diesel) is even more efficient because the mist goes directly into the combustion chamber and has almost no chance to clump into drops before being exposed to spark or the heat due to compression igniteing the fuel.But the most effective combustion would be a vaporized fuel.I realize furnaces are both thermaly efficient as well as fuel efficient.Which an auto engine couldn't begine to compare to.But combustion efficiency could stand improving.But most who have tried have vaporized the fuel to much,and left tar residues behind that are even more damaging then normal carbon deposits.While I don't deny the basic laws of thermodynamics,I do question some theories of application.Please try to understand the different aspects that are involved when considering efficiency.Thermaly,I personally doubt a 4 stroke piston engine will ever be practicle at more then 45 or 50% efficiency.My point of the coolant temps in Smokey's design were lower waste heat output due to better heat utilisation.And I know his design was supposedly later proven not to work and instead self destructed.But this was after showing others previously,for many hours of opperation which the press witnessed,that his engine worked well.He never sold his engine willingly to Chrysler.And I tend to suspect the engine was tampered with causing a convenient catastrophy.Is that an unreasonable thing to suspect?And I don't know what the parasitic power loss percentage is in a piston engine.I doubt if it can ever be much improved either.But my point all along was combustion waste.The main reason for catalytic converters.And thanks Moneypit for reminding me leaner mixtures create higher oxides of nitrogen emmissions.Considered as the main cause of acid rain,this alone could be the reason lean burn technology is supressed.
Last edited by Rick & Connie; 08-27-2005 at 12:39 AM. Reason: Addition |
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Efficiency Revisited
I do not know if I am the person that Rick & Connie allude to in terms of calling them "inexperienced fools" if that is the case, I sincerely apologize. It was not my intention to call anybody anything.
My only points were that the development of the gas engine is such that we can only expect marginal efficiency improvements on the thermal side. I think we will have better luck improving the propulsive efficiency that is: drag, transmission, rolling resistance, weight etc. Further improvements can come from the energy lost in braking and decelerating. In other words improving engine efficiency alone will no get us to 100 mpg. By adding the other two we have a good shot at achieving it. JL |
#50
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Back to the origional question
Besides better driving habits,tune up improvements and some types of modifications.The only gadget on the market that might work to improve mpg's without causing problems is called the turbonator or something like that.It's a device that fits under the air filter.What it does is to cause a swirling of the intake air which would help reduce the amount of fuel clumping into larger drops.Of course it would also cause a small drop in airflow cfm's.And it would be most effective in an engine where the air filter is over the intake manifold,as in most carburated designs and throttle body injection desings.Remote air filter and turbo engines probably would gain absolutly no benifits at all.Alot of race car engines have the intake passages in their heads ported in a spiraling pattern to help keep intake air volocity as high as possible,and create turbulance,to help in keeping the fuel as misted as they can.Nascar engines also have an insert directly below the carb,inside the manifold,for the same purpose.They call the insert a turtle.It helps prevent puddling of the fuel under the carb.Improves airflow,valocity,and helps keep the fuel mist suspended in the airflow instead of dropping out as droplets.
Last edited by Rick & Connie; 08-27-2005 at 01:13 AM. Reason: typo |
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I couldn't agree more
There are many different ways overall vehicle design effect the vehicles fuel efficiency.More aerodynamic designes.Lighter vehicles.And the only thing I LOVE about currant hybrids,the energy recovery in their braking systems.Something I've wondered about for hybrids.Instead of batteries,would capacitors work almost as well for energy storage?They have many times the lifespan.No hazardous materials to recycle.And many times lighter then most battery designs.And of course it couldn't hurt to teach smart driving for fuel efficiency as well as safety in driving schools and drivers-ed classes.These are only a few of the ways cars could be built for better efficiency.But none of them do any good as long as most people want to drive BIG FLASHY SUV's,huge Linkoln's,Caddy's,etc.Cadillac had a good idea when they introduced their 8/6/4 engine design.All the power of a V8,with the efficiency of a 4 cylinder.To bad about the bugs that engine design had though.
And no JL.While I was disheartened by you'r reply,I wasn't insulted.You posted what you know on the subject politely.It's just frustrating because of all the failures ridiculed by the automakers & media.That the few designs that do seem to work well aren't given a chance.Of course the true test would be for the design I saw working would be road testing for at least 80,000 miles.I experimented with a similar design once on a set of plans someone else bought.It was tried on a Pinto,and gave great milage.But the engine was destroyed by tar and varnish residues after about 4,000 miles. Last edited by Rick & Connie; 08-27-2005 at 01:55 AM. Reason: More info |
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Capacitors
I am not an expert on the subject, but I would think that in order to store the same amount of energy as a battery the capacitors woud be very large and work at a (variable) voltage much higher that 12 volts. That would be dangerous and probably very expensive.
JL |
#53
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Having said all that, I suspect that most people buying them today cannot justify the additional cost based on mileage. I think they have become somewhat "politically correct" and trendy. Driving one seems to make a political statement like, "I care about the environment enough to spend an extra $10,000, just to do my part." The same can be said for most people driving Hummers. What percentage of them can come up with a rational justification? I guess my point is that car buyers are not always "reasonable" and it's difficult to tell what they are going to do. Lastly, we can't forget potential tax breaks for buying hybrids (as well as other high efficiency vehicles). Quote:
What do you think? |
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Please correct me if I'm wrong
I haven't done very well here trying to discuss this with most of you.So I started another thread titled "A discussion on engine efficiencies".It's here in the tech help forum.
Craig,I think I started it in a way that shouldn't give you a headache.And I plan to keep it that way.I spelled out my understanding of thermal efficiency percentages.Mechanical efficiency percentages due to parasitic power loss.And combustion efficiency percentages.I understand the chemistry of fuel as far as vapor points and fuel being stored energy.I believe combined solar and chemical is correct?Please,everyone read what I've posted carefully,and correct me on any information I have wrong.I know there are many other factors involved in the operation of an engine.But these three factors are the primary ones governing all other aspects of an engines operation,correct? |
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About 5 years ago I went to Detroit and spent some time with representatives of several auto manufacturers. At the time, Ford had acquired the company that produced the Think electric car. While waxing eloquent over the design that allowed replacing only the battery cells that failed, I asked the Ford guy how long he thought owners would put up with replacing battery cells every few weeks until all had been replaced? Since all the battery cells would be the same age, cells that had not yet failed would certainly be living on borrowed time. I never got a satisfactory answer to that one, but I did get the Ford rep to admit that everyone at the meeting would be well into retirement before anyone put an electric car on the market that was not subsidized by either higher prices on conventional cars, or in the form of tax breaks. The technology was and is nowhere near the point of standing on its own virtues, and shall remain so for the foreseeable future. Quote:
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And as for the Enviro-wonks, my standard challenge is that I personally have done more to actually improve the environment than they have. Back in my shop days, I did emissions testing and performed emissions repairs. I'm still licensed by the state of Pennsylvania as an Emissions Repair Technician. All that fancy title means is that I was the guy you had to convince if you wanted an emissions waiver...but still. I've yet to meet a 'Greenie' who continued the argument past that point. Quote:
__________________
1989 300 SEL that mostly works, but needs TLC |
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