I'm trying to find more information about the EVAP system, and I'm having trouble. In addition to the exhaust system which I'm designing (which a number of you have helped me out on, thanks for that) I'm also doing the fuel system, and the engine we're using (Rotax 4 cylinder 4-stroke Aircraft Engine, carbureted, not FI) has obviously never needed an EVAP system. If anyone could steer me in the right direction for some more info, as well as some sources for parts, I would greatly appreciate it.
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EVAP System
- Thread starter MStiller
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BrianPetersen
Mechanical
What emission regulations will your end product be subject to?
- Thread starter
- #3
You will also need to comply with OBD-II diagnostic protocols outlined in SAE, take a look here:
and check with the California Air Resources Board for specific requirements.
Franz
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and check with the California Air Resources Board for specific requirements.
Franz
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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
- Thread starter
- #5
Can you have the OBD with a carbureted engine? It said on that OBD-II page Franz posted above that all cars since 1996 have had OBD, but the last time a new car had a carb in the US market was 1990....
Maybe I'm wrong, but I get the feeling someone is about to tell me I'm going to have to have fuel injection for this one
Maybe I'm wrong, but I get the feeling someone is about to tell me I'm going to have to have fuel injection for this one
- Thread starter
- #7
- Thread starter
- #8
In addition to the OBD-II stuff which will mean we need to design a FI system for the engine (I dont want to think about that, it makes me sad), does anyone know where I can get more info about the EVAP system? Because we're going to need that regardless, and I've been having a hard time getting a good explanation of exactly what it does, and what all of the parts are
I'm a bit surprised that you haven't had a detailed response on EVAP requirements so far, since (for automotive applications) it seems to have been a core part of emissions control in the USA for so long. Not so in Europe and the rest of the world, of course.
You are going to need to control fuel vapour emissions from:
- Refuelling activities
- Storage (are you using a plastic tank? How are you connecting the tank to the engine?)
- All fuel line connectors
_ The vapour storage cannister (if your project really needs it)
And your vapour cannister will need to be purged occasionally, when the operating conditions of the engine allow. An EFI system controller will normally have a calibratable control strategy to do this, how will your carburetted system cope if you only have an electronic spark system?
Do you think it would be worth studying a mass-produced motorcycle system for ideas?
What exactly is the project?
Bill
You are going to need to control fuel vapour emissions from:
- Refuelling activities
- Storage (are you using a plastic tank? How are you connecting the tank to the engine?)
- All fuel line connectors
_ The vapour storage cannister (if your project really needs it)
And your vapour cannister will need to be purged occasionally, when the operating conditions of the engine allow. An EFI system controller will normally have a calibratable control strategy to do this, how will your carburetted system cope if you only have an electronic spark system?
Do you think it would be worth studying a mass-produced motorcycle system for ideas?
What exactly is the project?
Bill
- Thread starter
- #10
We're building a lightweight composite vehicle. I've found some information about the general needs for it (i.e. the vapors from the tank are sent to the charcoal canister, and then added to the intake, etc. etc.) but i'm really looking for some exact details on everything that we'll need.
The whole reasoning for OBD-2 and upcoming OBD-3 is emission maintenance and monitoring. The vapor recovery system is only a part of it, along catalyst degredation, cold start emissions.
Since you state you are doing a composite vehicle and not a motorcycle, other requirements probably apply. Somewhere you will have to do SHED emissions testing as well, something that has been a problem for vehicles with certain non-metallic body parts and paint compositions.
The reason for fuel injection is that a carburetion system cannot provide the long term hands-off emission control required by the EPA for model year 1996 and newer vehicles.
Franz
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Since you state you are doing a composite vehicle and not a motorcycle, other requirements probably apply. Somewhere you will have to do SHED emissions testing as well, something that has been a problem for vehicles with certain non-metallic body parts and paint compositions.
The reason for fuel injection is that a carburetion system cannot provide the long term hands-off emission control required by the EPA for model year 1996 and newer vehicles.
Franz
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- Thread starter
- #12
Yeah, that I know, because with the FI engine, you can control the mixture based on the O2 sensor. The vehicle is NOT classified as a motorcycle, so it will need to adhere to standard passenger vehicle requirements. I've never heard of the SHED testing...what is that? Also, I realize the Evap system is only a part of the emissions control, but I've had no trouble getting a catalytic converter, while this has given me a lot more trouble in terms of both getting information and finding a parts source.
MStiller,
I dont want to be the bearer of bad news but I think that you are going to seriously struggle with this.
For a start, if you are trying to use a carb for fuelling control you are going to fail on the fedral/carb tailpipe out emissions tests, even with a cat. A situation that will only be exacerbated by you purging the charcoal canister.
If you decide to use an aftermarket EFI system you will probably still be a country mile away from where you need to be. These systems just do not posses the functionality that you require.
My best advice would be to speak to a automotive consultancy such as Ricardo, Lotus, Mahle, AVL, FEV, IAV etc etc to see what their take is on your plans.....
MS
I dont want to be the bearer of bad news but I think that you are going to seriously struggle with this.
For a start, if you are trying to use a carb for fuelling control you are going to fail on the fedral/carb tailpipe out emissions tests, even with a cat. A situation that will only be exacerbated by you purging the charcoal canister.
If you decide to use an aftermarket EFI system you will probably still be a country mile away from where you need to be. These systems just do not posses the functionality that you require.
My best advice would be to speak to a automotive consultancy such as Ricardo, Lotus, Mahle, AVL, FEV, IAV etc etc to see what their take is on your plans.....
MS
GregLocock
Automotive
Can I take a punt and guess that you are building an Auto X prize car?
If so I strongly recommend that you hook into the forums there.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
If so I strongly recommend that you hook into the forums there.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
- Thread starter
- #15
SHED - "Sealed Housing for Evaporative Determinations"
and as Franzh says, SHED can be an issue with 'conventionally' built vehicles, let alone something with high proportions of composites in its structure.
From what I can remember, legislation (may vary with geographical/political location) requires any new vehicle to be evaluated for certain chemical emissions over simulated environmental cycling periods.
The test result will include emissions from tyres, trim, polymer-based materials (dash panel, seat foam, door and glass seals, etc., etc.) in addition to stuff that you may have expected, like the engine and fuel system. So beware, products of curing processes that may be part of your hybrid body could be an issue.
And mattsooty is right. I don't know about the USA, but unless your vehicle is destined to be such a low manufacturing volume that special legal 'get outs' exist, as they can for one-offs or machinery, carburettors aren't going to figure anywhere in a serious attempt to get something into production.
Bill
and as Franzh says, SHED can be an issue with 'conventionally' built vehicles, let alone something with high proportions of composites in its structure.
From what I can remember, legislation (may vary with geographical/political location) requires any new vehicle to be evaluated for certain chemical emissions over simulated environmental cycling periods.
The test result will include emissions from tyres, trim, polymer-based materials (dash panel, seat foam, door and glass seals, etc., etc.) in addition to stuff that you may have expected, like the engine and fuel system. So beware, products of curing processes that may be part of your hybrid body could be an issue.
And mattsooty is right. I don't know about the USA, but unless your vehicle is destined to be such a low manufacturing volume that special legal 'get outs' exist, as they can for one-offs or machinery, carburettors aren't going to figure anywhere in a serious attempt to get something into production.
Bill
Further, a SHED test actually places a vehicle inside a sealed container (hence the appropriate acronym "shed"). All emission which are emitted from the vehicle are collected and measured. This is why many manufacturers are moving to water based paints.
In the US, ALL volume manufacturers must perform the SHED test along with a full EPA certified FTP-75/US-06 emission test. Small volume manufacturers have such tight restrictions on what constitutes a small volume as to be almost impractical (50 cars at 1.5 million each, or 5000 cars at $15,000 each, guess which one has a higher cost recovery ratio?)
1) To qualify for LEV or any level below that, you will HAVE to use a catalyst.
2) To keep the catalyst in its sweet spot, you will HAVE to use fuel injection.
3) To keep the fuel injection operating in its optimum range for catalyst efficiency, the electronic controls suite will have to be extensively refined. You are NOT going to find an off the shelf unit, it MUST be refined for your EXACT application. For example, the engine calibration for a 2006 Ford F-150 4.6 L engine is different than a 2006 Ford E-150 4.6.
You havent even gotten into crash testing yet.
I dont intend to dispel any good intentions you have, but to let you know what you are setting yourself up for.
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.
In the US, ALL volume manufacturers must perform the SHED test along with a full EPA certified FTP-75/US-06 emission test. Small volume manufacturers have such tight restrictions on what constitutes a small volume as to be almost impractical (50 cars at 1.5 million each, or 5000 cars at $15,000 each, guess which one has a higher cost recovery ratio?)
1) To qualify for LEV or any level below that, you will HAVE to use a catalyst.
2) To keep the catalyst in its sweet spot, you will HAVE to use fuel injection.
3) To keep the fuel injection operating in its optimum range for catalyst efficiency, the electronic controls suite will have to be extensively refined. You are NOT going to find an off the shelf unit, it MUST be refined for your EXACT application. For example, the engine calibration for a 2006 Ford F-150 4.6 L engine is different than a 2006 Ford E-150 4.6.
You havent even gotten into crash testing yet.
I dont intend to dispel any good intentions you have, but to let you know what you are setting yourself up for.
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
- #18
For the SHED testing as being a problem with the composites, is that because the epoxy just tends to add to the total emissions? We're using pre-preg, so I would think that once we've post-cured the vehicle, all of the epoxy is hardened and thats it, but maybe I'm wrong.
In terms of exemptions, truthfully, we were hoping we could get one for this vehicle. The carbureted engine is really just for our Proof-of-concept vehicle, which is just to prove to people that the thing actually works like we say it wlil. After that, when we hit production, we would switch to a FI engine (or even, GASP, a diesel!). But I'm fairly certain that if we were to even have a chance at getting an exemption, we'd need to demonstrate that we actually attempted to do our level best to meet the emissions standards, and we would say "Look, we tried really hard, we did everything we could in this situation to meet emissions standards, we promise we're going to change it as soon as we move into production so that it definitely will, but right now we're really poor and can't afford a different engine, etc. etc."
So on that note, if anyone knows of someone I could speak with regarding exemptions, that would be awesome.
In terms of exemptions, truthfully, we were hoping we could get one for this vehicle. The carbureted engine is really just for our Proof-of-concept vehicle, which is just to prove to people that the thing actually works like we say it wlil. After that, when we hit production, we would switch to a FI engine (or even, GASP, a diesel!). But I'm fairly certain that if we were to even have a chance at getting an exemption, we'd need to demonstrate that we actually attempted to do our level best to meet the emissions standards, and we would say "Look, we tried really hard, we did everything we could in this situation to meet emissions standards, we promise we're going to change it as soon as we move into production so that it definitely will, but right now we're really poor and can't afford a different engine, etc. etc."
So on that note, if anyone knows of someone I could speak with regarding exemptions, that would be awesome.
- Thread starter
- #19
A proper and independent SHED facility can be a rare thing.
I dare say there are many more in the USA than here in Europe, but even when you find one, you may also find that you could be sheduled well into the future as the type of testing can be in high depand. Don't expect it to be readily available.
I'm sure your countrymen will know, but Southwest Research in Texas might be a place to start.
Bill
I dare say there are many more in the USA than here in Europe, but even when you find one, you may also find that you could be sheduled well into the future as the type of testing can be in high depand. Don't expect it to be readily available.
I'm sure your countrymen will know, but Southwest Research in Texas might be a place to start.
Bill
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