I've had it. Gasoline is now $1/L. I can get propane for .45/L. My goal is to build a naturally aspirated propane Ford 2.3L for maximum power. I searched and found a few sources that say the max CR is around 11:1 (sketchy details as to why - I'm assuming emissions and timing come in to play). But the odd story tells of 15:1 being possible. My question is (emissions not withstanding) just how high can you go? Of course I'll invest in forged pistons, programmable timing controls, cooler thermostat, cooled intake manifold, cold plugs, hi torque starter, stainless valves, porting & polishing, and a few other power goodies. I live with engines and I've done conversions before and feel ready to tackle a real challenge. I can do a head swap and machining and get to about 14:1 CR. I've already done the work with the checking with the engine. It will all fit. I already know there are cheaper ways to go (eg turbo, bigger engine, etc)and gasoline 'may' be the best route overall. I would like to hear of actual cases where this has been attempted. I don't want to hear why this is a bad idea, but rather what WOULD it take to accomplish it. Thanks
Eng-Tips is the largest engineering community on the Internet
Intelligent Work Forums for Engineering Professionals
-
Congratulations waross on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
Propane to the max 1
- Thread starter firefrog
- Start date
-
1
- #2
Lets look at this scenario "I like steak, but only the way I cook it. The rest is garbage".
The same with LPG and for that matter, any engine fuel system. One recipe will not fit every application, each must be treated in its own unique way. There is NO one only way to do it, there are multitudes of variables.
Change the CR and the camshaft profile no longer is optimum. Change the piston crown and the head flow characteristics change. Change the rod length and the torque band moves around.
Not a bad idea, but one that needs considerable thought before dumping parts together. Even though I have built probably close to a thousand engines, every one was different with different demands and end-use requirements. For optimum performance, you can toss around carburetion, vapor single point fuel injection, multiport vapor injection, multiport liquid injection, then play with injector sourcing, injector timing, mapping, and so on.
Its easy to make an engine with 9:1 CR run and last, but when you bump the CR to 11:1 or higher, many things change. Do you want to run lean burn? Stoichiometric?
You ask what would it take to "accomplish it", what is it you are trying to accomplish?
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The same with LPG and for that matter, any engine fuel system. One recipe will not fit every application, each must be treated in its own unique way. There is NO one only way to do it, there are multitudes of variables.
Change the CR and the camshaft profile no longer is optimum. Change the piston crown and the head flow characteristics change. Change the rod length and the torque band moves around.
Not a bad idea, but one that needs considerable thought before dumping parts together. Even though I have built probably close to a thousand engines, every one was different with different demands and end-use requirements. For optimum performance, you can toss around carburetion, vapor single point fuel injection, multiport vapor injection, multiport liquid injection, then play with injector sourcing, injector timing, mapping, and so on.
Its easy to make an engine with 9:1 CR run and last, but when you bump the CR to 11:1 or higher, many things change. Do you want to run lean burn? Stoichiometric?
You ask what would it take to "accomplish it", what is it you are trying to accomplish?
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
- Thread starter
- #3
Thanks for the reply. Yeah I didn't mention the intended purpose. This will not be for a special application. The cost of daily driving is really p***ing me off. What I want is a driveable vehicle with a good amount of power and great fuel economy. I want to use stock or readily available aftermarket components - not too radical. Having said that, I won't be able to control the urge to mess with it. I have a few engines to rebuild and work with. I want to try some crazy ideas without killing myself. Especially, for now, I'm working on the intake manifolds. I've evened out the runner configuration and am working on this chilling aspect. I will be installing airconditioning exchangers before, then after the carburator (maybe both), then see what happens. Of course, there are challenges associated with this, but this in turn leads to the compression issue. With a very cold intake charge, I'm wondering how to take advantage of it. Again, I can think of many reasons why this won't work, but this isn't going to stop me from trying.
- Thread starter
- #6
While diesel is a viable alternative, I chose this engine for its low cost and versatility. I also need the propane for the cooling process (no moving parts). The first stage chiller will be coolant from the vaporizer. The actual vaporized (barely) propane will be routed first to the inside of the intake manifold. I will add methanol to the propane tank to keep the vaporizer and carburator from icing up. I can monkey with these things while the engine is together and in place. The compression ratio, however, is a little more difficult to alter, so I wanted to know where to set it before I begin.
You will only realize about 770 btu's from vaporizing a gallon of propane from ambient temp/pressurized liquid state to atmospheric pressure vapor. (Latent heat of vaporization) This is not enough to lower the charge air temperature any significant amount. Propane air fuel ratio by volume is roughly 24:1 (not the stoichiometric ratio), so any heat transfer/absorbtion to the charge air would be negligible.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
firefrog,
Sounds like an interesting project, but keep in mind that with its low density, Propane has a lot less BTU/gallon than gasoline. You will have to burn more propane to go a mile than you would gasoline, which will eat up much of the fuel cost difference.
Sounds like an interesting project, but keep in mind that with its low density, Propane has a lot less BTU/gallon than gasoline. You will have to burn more propane to go a mile than you would gasoline, which will eat up much of the fuel cost difference.
Funny story. I bought a propane/gas hybrid from Renault over here in France in 2000. Other than the valves burning out after 10 thousand miles, which is quite common for reasons discussed elsewhere on eng-tips, I did the math and finally sold it. On the highways here you can go 130 kph. I do mostly highway driving and discovered that propane has terrible milage when you go that fast. I was averaging about 22 litres for a 100 kilometers. Call it approx. 4 litres for a us gallon, that's 5.5 gallons for 60 miles, or just over 10 mpg! Woops! At 75 mph with gasoline I was getting a tad over 20 mpg. So I sold the Renault and bought a diesel tdi VW Bora. That thing got 6 litres to a 100 klicks on average. I even did some high speed driving in Germany (about 110 mph average over 3 hours) and the milage went down to...to 7 litres for a 100 klicks! (in mpg thats 45 mpg down to under 40 mpg. approx.)
Curious, I looked on an French LPG website extolling the virtues of LPG and quoting its low emissions levels in CO2...per litre!
So I did the math. A diesel, getting 6 to 7 litres per 100 kilometers, or LPG, getting 15 to 22 litres per 100 kilometers.
I was sending less CO2 into the environment with the diesel!
LPG was half price diesel, so I ended up paying more at the pump for the LPG as well to go the same amount of kilometers (and LPG price is subsidized in France as well). Of course, of course, if you never go over 40 mph, propane milage rates stabilize at roughly that of gasoline. Then we get back to those burned valves (repaired on warranty btw).
You're wasting your time if you're going to drive propane on the highway, modern tdi diesels whip its little bottom.
blakev
Curious, I looked on an French LPG website extolling the virtues of LPG and quoting its low emissions levels in CO2...per litre!
So I did the math. A diesel, getting 6 to 7 litres per 100 kilometers, or LPG, getting 15 to 22 litres per 100 kilometers.
I was sending less CO2 into the environment with the diesel!
LPG was half price diesel, so I ended up paying more at the pump for the LPG as well to go the same amount of kilometers (and LPG price is subsidized in France as well). Of course, of course, if you never go over 40 mph, propane milage rates stabilize at roughly that of gasoline. Then we get back to those burned valves (repaired on warranty btw).
You're wasting your time if you're going to drive propane on the highway, modern tdi diesels whip its little bottom.
blakev
firefrog,
I too have had it with high priced gasoline. Between my wife and I, we spend over $5,000 USD on gasoline per year at current pricing. Switching to LPG, again with current pricing, I should be able to get that to less than $3,000.
I have searched the internet over and researched many different sites. There is a lot of information out there, but most of it is sketchy or incomplete enough to actually implement an efficient LPG system on a vehicle.
First off - the components for a propane system:
1) A wet tank - holds and delivers propane in a liquid form.
2) A "high-pressure" liquid propane regulator - preferably with an overflow shutoff for safety. This is to bring the pressure down lower but yet maintain a liquid form until you want it to be a gas. The overflow shutoff is to shut down the supply should to much propane be flowing out - i.e. broken line, etc..
3) A vaporizer - this is simply something to bring the liquid propane up to vaporization temperature. Could be as simple as copper tubing coiled up in the engine compartment.
4) A "low-pressure" vapor propane regulator - so you get a controllable low pressure to the fuel delivery point.
5) A controllable delivery method - either a venturi based diaphragm carburetor - or a direct injection method.
I did a few tests on my current vehicle (1997 chrysler V6 MPI 2.5L) with "stub-in" LPG. It seemed to run the engine just fine - I do not know how long it would last or how much wear was taking place. There is conflicting information on that subject all over the web.
From what I can find, the "best" method (meaning most efficient $/mile in my book) is to direct inject either vapor or liquid. I actually tried this on my vehicle and quickly found that the injectors were not sized proper for injecting propane vapor. It would almost fire up but not quite enough to run. This tells me that they must be fairly close in size - just not big enough.
There are several companies across the world that are making injectors to use for direct injecting propane vapor. Trouble is, they only sell to OEM's and I would just imagine the cost would be beyond payback for me.
I have a few ideas on how to make this injection system work. My goal is to use the existing engine control computer with little to no modifications.
1) stub-in enough LPG into the intake manifold to make the car idle - then use the injectors to only control the difference needed for higher RPM's. I need to think this one through a little more yet. The curves for air/fuel ratio are most likely different - maybe use some sort of linkage from the throttle position to the stub-in valve to keep the "difference" within range of the injectors.
2) make or modify existing gasoline injectors. This one may get a little tough. I would assume I'd need a longer stroke per pulse to get more propane vapor into the engine. I'd have to modify the feedback signal also.
3) What else? Anyone have any ideas?
I totally agree with the statement "I don't want to hear why this is a bad idea, but rather what WOULD it take to accomplish it" from firefrog's first post. The pessimism gets to be a bit overwhelming at times.
Thanks for any and all input.
I too have had it with high priced gasoline. Between my wife and I, we spend over $5,000 USD on gasoline per year at current pricing. Switching to LPG, again with current pricing, I should be able to get that to less than $3,000.
I have searched the internet over and researched many different sites. There is a lot of information out there, but most of it is sketchy or incomplete enough to actually implement an efficient LPG system on a vehicle.
First off - the components for a propane system:
1) A wet tank - holds and delivers propane in a liquid form.
2) A "high-pressure" liquid propane regulator - preferably with an overflow shutoff for safety. This is to bring the pressure down lower but yet maintain a liquid form until you want it to be a gas. The overflow shutoff is to shut down the supply should to much propane be flowing out - i.e. broken line, etc..
3) A vaporizer - this is simply something to bring the liquid propane up to vaporization temperature. Could be as simple as copper tubing coiled up in the engine compartment.
4) A "low-pressure" vapor propane regulator - so you get a controllable low pressure to the fuel delivery point.
5) A controllable delivery method - either a venturi based diaphragm carburetor - or a direct injection method.
I did a few tests on my current vehicle (1997 chrysler V6 MPI 2.5L) with "stub-in" LPG. It seemed to run the engine just fine - I do not know how long it would last or how much wear was taking place. There is conflicting information on that subject all over the web.
From what I can find, the "best" method (meaning most efficient $/mile in my book) is to direct inject either vapor or liquid. I actually tried this on my vehicle and quickly found that the injectors were not sized proper for injecting propane vapor. It would almost fire up but not quite enough to run. This tells me that they must be fairly close in size - just not big enough.
There are several companies across the world that are making injectors to use for direct injecting propane vapor. Trouble is, they only sell to OEM's and I would just imagine the cost would be beyond payback for me.
I have a few ideas on how to make this injection system work. My goal is to use the existing engine control computer with little to no modifications.
1) stub-in enough LPG into the intake manifold to make the car idle - then use the injectors to only control the difference needed for higher RPM's. I need to think this one through a little more yet. The curves for air/fuel ratio are most likely different - maybe use some sort of linkage from the throttle position to the stub-in valve to keep the "difference" within range of the injectors.
2) make or modify existing gasoline injectors. This one may get a little tough. I would assume I'd need a longer stroke per pulse to get more propane vapor into the engine. I'd have to modify the feedback signal also.
3) What else? Anyone have any ideas?
I totally agree with the statement "I don't want to hear why this is a bad idea, but rather what WOULD it take to accomplish it" from firefrog's first post. The pessimism gets to be a bit overwhelming at times.
Thanks for any and all input.
You cannot look at the positives without considering the negatives.
Certainly you can cobble enough parts together to make it run, but at what price and I dont mean just money. Just dumping LPG into the intake manifold to get it to idle accomplishes nothing, and gasoline injectors cannot handle enough flow volume for LPG vapor, plus they cannot work with a vapor fuel, no cooling and lubrication.
There are NO direct injection LPG systems available anywhere, and only a few hand built units being tested in world class laboratories. Port injected systems are available for a few select systems, the R&D time and cost to develop a operable system for a new platform is extensive/expensive.
There are three schools of thought:
1) what is called "core technology" where propane vapor is metered at the throttlebody with either a mechanical carburetor designed specifically for propane, or a venturi, each requireing specifically designed regulators and vaporizers. The problem with this system is the intake manifold is filled with a combustible fuel/air mixture and any little combustion gas seeping past an intake valve and the manifold is history. Plus, the fuel metering is very inefficient, there is too much air and fuel to make any changes precise enough.
2) propane vapor injection, with special vapor injectors with pressure regulator/vaporizers to reduce propane pressure to the desired amount (ranging from about 20 to 80 psig) along with any electronic support tools.
3) liquid injection, where propane liquid is pulled from the tank and injected without pressure reduction. Pressures can reach 400 psig and blow apart any gasoline injector.
The injection systems on the market can operate with the OEM computer, providing the fuel pressures are controlled exactly, the injector size is precisely matched to the engine demand, and some additional computer interface is frequently needed. Underhood and fuel tank heat is a real problem with liquid injection systems.
I know of one company that designed a good vapor injection system for a 2004 Chevy Impala, and it cost over $100,000 before they got it right. Problem is that they are having trouble selling enough kits to recoup the investment in development.
Although what I write may seem like a doom-sayer, I have spent the better part of my 38 year career with fuel systems and encourage the responsible use and R&D with LPG. LPG is a great fuel and has its place in our economy, but just dont try and compare it with gasoline or diesel on a one to one basis, it doesnt exist. Put them in physical property terms and LPG can shine like almost no other fuel though.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Certainly you can cobble enough parts together to make it run, but at what price and I dont mean just money. Just dumping LPG into the intake manifold to get it to idle accomplishes nothing, and gasoline injectors cannot handle enough flow volume for LPG vapor, plus they cannot work with a vapor fuel, no cooling and lubrication.
There are NO direct injection LPG systems available anywhere, and only a few hand built units being tested in world class laboratories. Port injected systems are available for a few select systems, the R&D time and cost to develop a operable system for a new platform is extensive/expensive.
There are three schools of thought:
1) what is called "core technology" where propane vapor is metered at the throttlebody with either a mechanical carburetor designed specifically for propane, or a venturi, each requireing specifically designed regulators and vaporizers. The problem with this system is the intake manifold is filled with a combustible fuel/air mixture and any little combustion gas seeping past an intake valve and the manifold is history. Plus, the fuel metering is very inefficient, there is too much air and fuel to make any changes precise enough.
2) propane vapor injection, with special vapor injectors with pressure regulator/vaporizers to reduce propane pressure to the desired amount (ranging from about 20 to 80 psig) along with any electronic support tools.
3) liquid injection, where propane liquid is pulled from the tank and injected without pressure reduction. Pressures can reach 400 psig and blow apart any gasoline injector.
The injection systems on the market can operate with the OEM computer, providing the fuel pressures are controlled exactly, the injector size is precisely matched to the engine demand, and some additional computer interface is frequently needed. Underhood and fuel tank heat is a real problem with liquid injection systems.
I know of one company that designed a good vapor injection system for a 2004 Chevy Impala, and it cost over $100,000 before they got it right. Problem is that they are having trouble selling enough kits to recoup the investment in development.
Although what I write may seem like a doom-sayer, I have spent the better part of my 38 year career with fuel systems and encourage the responsible use and R&D with LPG. LPG is a great fuel and has its place in our economy, but just dont try and compare it with gasoline or diesel on a one to one basis, it doesnt exist. Put them in physical property terms and LPG can shine like almost no other fuel though.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Thanks for the feedback. In looking at your biography, I expected nothing less from you in particular. With all due respect, sometimes you need to put the book down and try something. Engineering and Research is nothing more than an art of attempting to know everything that may affect your particular project - That is just plain impossible.
I could go on and start defending what I have done and what I will do - but that is just not goal oriented.
I will say that I may have not used the proper terminology as I have only begun to look into this area - by saying direct inject propane vapor - I see now that I should have said port inject propane vapor - that would be #2 on your list.
I'd like to know your thoughts on the idea of using a stub-in method in conjunction with the OEM injectors thus reducing the flow requirements of the OEM injectors.
Do you think there would be enough gain in efficiency versus a using just a mixer/carb?
Just to be clear - This would be for the vapor injection method. Yes I realize there would be some challenges in lubrication and cooling - put that aside for the moment - it is able to be overcome. Also, the notion that an intake full of a combustible fuel/air mixture is a bad thing just does not make sense to me. Have you ever seen how much combustible mixture gets created by a set of Holley 650 double pumpers?
The other components in the system are easy enough to get and implement although a bit of trial and error on getting all the final tweaks may be neccessary.
Again, thanks for any and all input.
I could go on and start defending what I have done and what I will do - but that is just not goal oriented.
I will say that I may have not used the proper terminology as I have only begun to look into this area - by saying direct inject propane vapor - I see now that I should have said port inject propane vapor - that would be #2 on your list.
I'd like to know your thoughts on the idea of using a stub-in method in conjunction with the OEM injectors thus reducing the flow requirements of the OEM injectors.
Do you think there would be enough gain in efficiency versus a using just a mixer/carb?
Just to be clear - This would be for the vapor injection method. Yes I realize there would be some challenges in lubrication and cooling - put that aside for the moment - it is able to be overcome. Also, the notion that an intake full of a combustible fuel/air mixture is a bad thing just does not make sense to me. Have you ever seen how much combustible mixture gets created by a set of Holley 650 double pumpers?
The other components in the system are easy enough to get and implement although a bit of trial and error on getting all the final tweaks may be neccessary.
Again, thanks for any and all input.
GregLocock
Automotive
Have you ever seen an intake system in an LPG fuelled vehicle blown apart in a backfire?
It was a regular occurence round here when we were developing a dual fuel car.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
It was a regular occurence round here when we were developing a dual fuel car.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
Drlap:
An intake manifold filled with a gaseous fuel mixture has a considerable explosive capability. Enough to blow a hood up after destroying the latch and hinges, shatter the air cleaner, blow apart the mass airflow sensor, twist the throttleshaft butterfly into a "U" shape, blow intake valves open, and let pieces into the engine. One Ford 5.4 engine I was driving cost more than $5,000 to repair (all the above). This was using core technology.
If you choose to "Just to be clear - This would be for the vapor injection method. Yes I realize there would be some challenges in lubrication and cooling - put that aside for the moment - it is able to be overcome." put aside your concerns, somewhere you will need to address them. That is what Engineering is, and it is NOT impossible, just a hurdle. That is why the multiwafer PC board was not invented in the 1950's, the transistor was not designed by Thomas Edison, and Benjamin Franklin did not invent the airplane. They may have had ideas on what would be possible if some technology existed "someday", but not now.
Now for the other side:
I applaude your intrest, keep it up. But please look at the total picture, and consider the "what if's" and address them at the same time as the positive's. In the end, you should have more positives than negatives.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
An intake manifold filled with a gaseous fuel mixture has a considerable explosive capability. Enough to blow a hood up after destroying the latch and hinges, shatter the air cleaner, blow apart the mass airflow sensor, twist the throttleshaft butterfly into a "U" shape, blow intake valves open, and let pieces into the engine. One Ford 5.4 engine I was driving cost more than $5,000 to repair (all the above). This was using core technology.
If you choose to "Just to be clear - This would be for the vapor injection method. Yes I realize there would be some challenges in lubrication and cooling - put that aside for the moment - it is able to be overcome." put aside your concerns, somewhere you will need to address them. That is what Engineering is, and it is NOT impossible, just a hurdle. That is why the multiwafer PC board was not invented in the 1950's, the transistor was not designed by Thomas Edison, and Benjamin Franklin did not invent the airplane. They may have had ideas on what would be possible if some technology existed "someday", but not now.
Now for the other side:
I applaude your intrest, keep it up. But please look at the total picture, and consider the "what if's" and address them at the same time as the positive's. In the end, you should have more positives than negatives.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
I think you are trying to re-invent the wheel drdap. There are dozens of gaseous sequential injection LPG kits with everything you need, including injectors and LPG ECU. I’ve just installed one on my car for 1500€. The setup process is very easy. First you will drive a few miles while LPG ECU acquires gasoline injection times. Than you will have a gasoline injection map (first you have to connect a notebook to the LPG ECU). Software than applies a theoretical multiplier to this map to obtain a LPG injection map. You will fine tune this map latter, by increasing or decreasing LPG injection times by steps of 1%. To do this you have the aid of the lambda sensor which is connected to the LPG ECU, too. Injectors lay on a common-rail so you only have to drill your inlet manifold as near as possible to the inlet valves to mount the nipples connected to the injectors by flexible tubes. Engine starts on gasoline than changes automatically to LPG when a set of conditions are fulfilled (vaporizer temps, rpm increase or decrease, etc.), all of this conditions can be changed by you. These kits are universal, only injectors size and number and vaporizer size change...just do a search on the net.....
These kits are not available here in the US, primarily due to the size engine (about double what is in Europe) and the US propensity for HD-5 propane instead of Autogas. HD-5 has a higher pressure than Autogas which causes some problems with regulator pressure controls. I have experimented with several European based systems and they do indeed work wonderfully, on engines in the 1.5 to 3L range. They are just now reaching the US shores in larger engine capability. However, they are not available for the DIY'er.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Might want to keep an eyeball on these fellows... looks interesting.
BTW, you didn't mention if your 2.3L Ford was the Lima designed Pinto engine or the Cosworth assisted Duratech unit.. ?
BTW, you didn't mention if your 2.3L Ford was the Lima designed Pinto engine or the Cosworth assisted Duratech unit.. ?
There must be plenty of propane conversion kits available. Impco makes both natural gas and propane kits. We converted a GM pickup truck to CNG in university, that was in 1991. Standard off the shelf parts. Same deal with propane.
The challenge with all gaseous fuels is that they displace the air that would otherwise be in the cylinder. Hence you need high compression and high timing to get some of that power back.
Guys, there is *nothing* new about gaseous fuels, natural gas or propane. The info is out there, the vendors are there, fuel distribution is the biggest problem.
If you want to try a radical approach without really killing yourself - try this:
1. Change your driving habits. I'll bet a small portion of the Prius' efficiency is due to the fact that there's a MPG meter and energy meter front and center on the dash. Get a mpg meter, or make one. Make a game of trying to get the most fuel economy. I did this with my Subaru - and was able to eke out about 10% improvement (albeit I drove like Granny).
2. Lighten up your car. Take everything out of it to reduce inertia and hence power required for acceleration. Spare, jack, floor mats, junk, even interior panels and extra seats. Switch to skinny tires on aluminum rims - save 8-10lbs a rim easy. Alumimum underdrive pulleys. Plastic hood. Saran wrap rear window (well not that crazy). Hey, you said radical.
3. Load up on MSDs and big gap plugs and try to tune your car for lean burn, if not all the time, during light load cruise on the highway. Shoot for high 20s in AFR. NOx emissions will hurt, but if you can get it to run smooth, the HCs and COs will be reasonable.
4. Figure out a way to shut cylinders down during cruise. Can you do that on a 4 cylinder? GM is reintroducing the V-8-6-4.
Some of this is real, some tongue in cheek, but its all doable, and another approach.
Denis Kefallinos
The challenge with all gaseous fuels is that they displace the air that would otherwise be in the cylinder. Hence you need high compression and high timing to get some of that power back.
Guys, there is *nothing* new about gaseous fuels, natural gas or propane. The info is out there, the vendors are there, fuel distribution is the biggest problem.
If you want to try a radical approach without really killing yourself - try this:
1. Change your driving habits. I'll bet a small portion of the Prius' efficiency is due to the fact that there's a MPG meter and energy meter front and center on the dash. Get a mpg meter, or make one. Make a game of trying to get the most fuel economy. I did this with my Subaru - and was able to eke out about 10% improvement (albeit I drove like Granny).
2. Lighten up your car. Take everything out of it to reduce inertia and hence power required for acceleration. Spare, jack, floor mats, junk, even interior panels and extra seats. Switch to skinny tires on aluminum rims - save 8-10lbs a rim easy. Alumimum underdrive pulleys. Plastic hood. Saran wrap rear window (well not that crazy). Hey, you said radical.
3. Load up on MSDs and big gap plugs and try to tune your car for lean burn, if not all the time, during light load cruise on the highway. Shoot for high 20s in AFR. NOx emissions will hurt, but if you can get it to run smooth, the HCs and COs will be reasonable.
4. Figure out a way to shut cylinders down during cruise. Can you do that on a 4 cylinder? GM is reintroducing the V-8-6-4.
Some of this is real, some tongue in cheek, but its all doable, and another approach.
Denis Kefallinos
Mr. Dman1.
Since 1996, the EPA limits what vehicles may be converted by requiring FTP-75 emission testing, and since April 1, 2002, ALL converted vehicles MUST have CARB or EPA certified fuel systems installed, no exceptions.
Standard off the shelf parts no longer applies to the every day vehicle. I remember well the days going to parts bins and grabbing a basket full of parts and trying them to see what works best, then getting it out the door to the consumer with no more tuning than a tachometer to set the idle mixture, or later, a 4 gas analyzer. The fuel system must now have full EPA certs, and be vehicle engine family specific.
Your second set of points is certainly with merit though. Point 3 is not possible with a conventional vehicle, and having a vehicle run in the high teens for AFR is difficult enough, let alone the high 20's. Since most of the emission laws and technology today are focused on NOx control, running lean burn has been shifted out of primary focus.
The GM skip-fire system (also used by Chrysler and others) is not as simple as killing spark, the intake valve and injector must also be disabled, again out of the realm for the DIY'er. GM spent close to $6 million getting their system to the point where it is today, not perfect, but not bad either.
BTW, nice Buick.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Since 1996, the EPA limits what vehicles may be converted by requiring FTP-75 emission testing, and since April 1, 2002, ALL converted vehicles MUST have CARB or EPA certified fuel systems installed, no exceptions.
Standard off the shelf parts no longer applies to the every day vehicle. I remember well the days going to parts bins and grabbing a basket full of parts and trying them to see what works best, then getting it out the door to the consumer with no more tuning than a tachometer to set the idle mixture, or later, a 4 gas analyzer. The fuel system must now have full EPA certs, and be vehicle engine family specific.
Your second set of points is certainly with merit though. Point 3 is not possible with a conventional vehicle, and having a vehicle run in the high teens for AFR is difficult enough, let alone the high 20's. Since most of the emission laws and technology today are focused on NOx control, running lean burn has been shifted out of primary focus.
The GM skip-fire system (also used by Chrysler and others) is not as simple as killing spark, the intake valve and injector must also be disabled, again out of the realm for the DIY'er. GM spent close to $6 million getting their system to the point where it is today, not perfect, but not bad either.
BTW, nice Buick.
Franz
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
- Status
Similar threads
- Locked
- Question
- Locked
- Question