New Fuel Economy Information site

[RealityRacer]

Hey mpgmike, I am new on this forum but just saw your link to one of your posts.
From that information you provided, are you saying we can get more efficiency from our engines without ruining emissions control?
What would this do to power output?

I have tried in the past to get better fuel efficiency from my truck but it capped out at 7% increase in mpg and nothing else I did would help.
What would you recommend?

[mpgmike]

Let me start with the fuel economy/emissions trade-off thought. When we had the X-Prize Sonata tested at Roush, we were given a 40% increase in fuel economy -- from stock 30 HWY to 42. All emissions were under EPA limitations. And in fact, all were below Hyundai's posted numbers as acceptable. The vehicle had about 40k miles on it when tested.

Some years ago I spoke with a chief engineer at a Canadian CNG retrofit manufacturing company. He told me that every January 1, all of their certifications became null and void. They had to find a clean vehicle for every chassis/engine/model year they wanted certified for that calendar year. Step 1 was to certify it as a clean slate, where it had to meet manufacturer's posted numbers for what emissions should be. Next step was to install their system and retest. He said that in all the years he had been doing that, they NEVER had a "clean" vehicle pass without massaging the daylights out of it.

With that said, in my opinion EPA and CARB (the 2 entities I've had to become familiar with) are 5% about pollution and 95% about making money. Case in point, if a CNG system was certified last January, the vehicles didn't change, the CNG system didn't change, why does EPA require another $10,000 per vehicle to recertify again next January?!?

Next point; as stated, not one of the vehicles this CNG company used for certification would pass in stock form. They would often buy them from a dealer and drive them straight to the test facility -- brand new! Sometimes they would try to get them with a couple thousand miles on them so at least the rings were seated. Didn't matter. Are vehicles as clean as statistics would suggest? If you improve combustion efficiency, are you really increasing pollution?? We now have a rather high-end EMS 5003 5-gas analyzer we use when testing technologies. It's portable with a 12 volt power plug, and with the Lab View software, we can simulate the type of data in the Roush Report. It may not be certifiable, but at least we know if we're increasing or decreasing emissions.

Lastly, many of the technologies we advocate for automobiles we first tested on small engines. There is no computer, so we can control things ourselves. For some projects we have even computerized the small engine so we have digital signal processor accuracy over the controls.

Lots of folks try fuel economy tricks only to have them cause a Check Engine Light (CEL). Curiously, the same tricks sometimes work on other vehicles with no CEL. In reality, someone needs to have an understanding of their vehicle when modifying it. It will have its own personality. For the average person, it would be nice to know someone that is an expert in that field, that has a broad range of knowledge concerning fuel economy. It's a much shorter learning curve when you only need to learn what makes your own personal car tick.

[RealityRacer]

Thanks mpgmike!
So engine efficiency can be increased and actually lower emissions?
What will engine efficiency do to power output?
I see on on your previously posted link a few good tricks to get better engine efficiency but what is there to help overcome ECU limitations on MPG?

[freebeard]

While we're [not] on the subject, what benefit would accrue to a freevalve conversion on a VW boxer four head?

[mpgmike]

Originally Posted by freebeard

While we're [not] on the subject, what benefit would accrue to a freevalve conversion on a VW boxer four head?

I was somewhat familiar with the concept of electronically actuated cylinder valves, but I had never heard of Freevalve. I had to look it up. It seems only Koenigsegg is using it in production. I know BMW (and probably other OEMs) looked into it in the past. There was one article I found where it looked like a hobbiest was able to fab up something and control it with an Arduino.

One thing is highly probably; if you have the know-how to make your own, mount it into a VW head, create an appropriate controller, with an HID (USB connected to a laptop?), AND program the software/tune it, it will definitely help. However, it is currently still out of the reach of average folks. The same energy invested into a Freevalve conversion would more likely than not deliver much greater gains invested elsewhere (in my opinion).

I've never played with electronically actuated valves, but did have the opportunity to play with Omni Valves. An internet search will turn up the wrong company. It was a 2-piece intake valve with a slider ring that interfaced with the valve seat. It worked on the principle of pressure differential. If you still had more pressure in the cylinder than the intake manifold, the ring would be forced closed. Once the pressure in the cylinder was lower than the manifold, it would pull the ring up and allow the intake charge to start flowing. When I played with them, they were marketing primarily to off-road engines for rock crawling. Engines could be idled down to <400 RPM, and the low-end torque was off-the-charts due to eliminating reversion.

[mpgmike]

Originally Posted by RealityRacer

Thanks mpgmike!
So engine efficiency can be increased and actually lower emissions?
What will engine efficiency do to power output?
I see on on your previously posted link a few good tricks to get better engine efficiency but what is there to help overcome ECU limitations on MPG?

Back in the 1920's through 1940's a brilliant genius named George Arlington Moore pioneered more radical technologies for the internal combustion engine than anyone else. In fact, he holds (or at least held for several decades) the record for the most ICE related US Patents of any single individual. Reading through his writings (and many other inventors over the past century), references to emissions dictated exactly what was coming out of the engine. These folks weren't working with our modern catalyst system. Reading through practically anything pertaining to engine efficiency over the past 50 years, there is a mandatory section that describes how the technology interplays with the catalytic converters.

In a perfect world (Faraday, among others, say it does not exist), ALL of the HC fuel would oxidize inside the combustion chamber and emit only water vapor and carbon dioxide. In our real world, there is always some amount of the fuel that either doesn't burn at all (HC emissions), or only partially burns (CO emissions). To complicate things further, in the heat of combustion, the danged air tries to burn forming NO and NO2 emissions!

With that said, a good rule of thumb regarding the cats; less emissions in = less emissions out. It can only be a "rule of thumb" because in reality, the cats work only when hot. Where does the heat come from? Exhaust gasses still burning out the exhaust manifold, and HC & CO burning inside. If the cats cool, you better hope you have 0 PPM HC and 0.000% CO coming out the engine if you want ultra clean exhaust! Then there is the NOX reduction catalyst. It works not only by heat (as the primary cat does), but also by the absorption and release of oxygen. It needs some oxygen sometimes, and a pretty-much oxygen-free exhaust feed at others. It oscillates back and forth, absorbing, then releasing oxygen. It tries to pull the oxygen from the NOx and release it as O2.

My experience is that you can run the engine at extreme levels of combustion efficiency where the cats aren't doing much. Allow the ECU to occasionally dump a little extra fuel to stoke up the fires, and the emissions are squeaky clean, you're getting ~50% better fuel economy (that number chosen random), the cats are working awesome -- and no CEL comes on!

One trick I learned is to wrap the exhaust between the engine and cat with a fiberglass header wrap. It holds the heat in. This does 2 things; your under-hood temps are lower, allowing longer life on belts, hoses, and even gaskets. It also keeps the cat hotter when improved combustion efficiency isn't feeding it as much HC/CO fuel.

Specifically pertaining to emissions, gains in the <40% to 50% range -- where combustion efficiency was improved -- almost never negate emissions. Above that, there arises a conflict between the catalyst functionality and an engine that's "too efficient". (If you research the Honda CVCC, you can learn much!) As for fuel economy gains, my experience is that the ECU rarely gives up more than 10% to 15% fuel economy increases, even if you improved combustion efficiency by 50% or more! There are parameters the ECU will not trespass. At this point, you need a bit of help (one of the things we have conquered).

Regarding power output, that's the EASY part! By definition, improving Combustion Efficiency means you are converting more of the chemical energy in the fuel to power at the crankshaft. POWER GOES UP! My approach of improving fuel economy is based on improving combustion efficiency so it requires less throttle to maintain speed (or get up to speed). Less throttle = less air AND less fuel (at any AFR).

[freebeard]

The Miata guy brought it into the realm of DIY, but I don't see a solution that doesn't increase the overall width of the engine. Still there are those performance claims.

I had high hopes for the Suderi Split Cycle Engine. But the inventor's heirs blew through the capital and folded.



They made their own proprietary inline four for test purposes. I think they could have developed on a VW flat four to their advantage. With differing cylinder sizes and custom crank offsets (maybe a roller bearing crank? Those are built up). Air reservoir for regenerative braking.

There exists an air compressor conversion, by Dunn-Right.

dunnrightinc.com
Home [dunnrightinc.com]
This camshaft allows two cylinders to run in their original fashion (four cycle) and the other two to pump air (two cycle). These conversions use the original VW cylinder heads and valves on the pumping and running cylinders. This provides for a high speed, trouble free operation. All you need is a dual port type I or type III VW Engine!

[mpgmike]

I seen something like that in the past. As I understand it, one cylinder performs a 1st-stage vaporization & homogenization on the fuel, then pressurizes it and feeds it into a 2nd-stage cylinder where the energy is actually extracted. Only the 2nd cylinder has a spark plug. Maybe what I saw was someone else's version, but the concept bears merit.

George Arlington Moore developed an engine concept back in the 1920's (I'd have to look it up to be exact) that used a static compression of 16:1! He used a modified camshaft that would hold the intake valve open about 1/2 way up the compression stroke. This delivered a dynamic compression ratio of about 8:1. This yielded 2 major benefits:

1) The engines were all carbureted at the time. By drawing an air/fuel charge into the hot cylinder, letting it swirl around a bit, then pumping 1/2 of it back into the intake manifold, the next cylinders intake stroke drew in a high percentage of vaporized and homogenized air/fuel. This dramatically improved combustion efficiency and reduced emissions. (George always included emissions in his writings -- quite revolutionary for the time.)

2) Bleeding off 1/2 the intake charge delivered a dynamic 8:1 compression ratio, so the engine worked well with typical fuel. However, on the power stroke, it delivered a 16:1 expansion ratio. This enabled harnessing far more of the energy from the fuel -- mechanically! This is one of the major advantages diesels have over gasoline engines -- higher expansion ratio.

[Ecky]

Originally Posted by RealityRacer

I am trying to understand your efforts for innovation and I am looking for answers. Can anyone here answer my questions? Surely, someone has some insight. You all seem very intelligent...
1. An ICE is 20% efficient and there is no room for improvement or the OEMs would do it. Can this be improved?
2. The ECU is programmed to adjust for max efficiency. Is there any evidence that the ECU is limited to a specified MPG?
3. Do you really think we want to be dependant on foreign oil? I mean, would there be any reason to keep us addicted to oil?
Please educate me- I am looking for answers.

1) Honda and Toyota both sell cars that have 40% efficient ICEs in them. Maybe a percent or two extra can be squeezed out of gasoline engines with higher compression and reducing parasitic losses, but that's already pretty close to the reasonable upper limit, without scavenging waste heat. Mercedes has a racing engine that broke 50% efficiency by scavenging exhaust heat.

2) None. Manufacturers spend millions of dollars chasing tenths of a percent, and there is a lot of incentive for them to improve things. The major losses in cars that exist now are (best I understand it) limitations put on engineers due to styling needs, power needs, or cost saving measures.

3) I agree we don't want to be. The US is a major oil producing nation. I don't fully understand why we buy a lot of oil.

[mpgmike]

2) None. Manufacturers spend millions of dollars chasing tenths of a percent, and there is a lot of incentive for them to improve things. The major losses in cars that exist now are (best I understand it) limitations put on engineers due to styling needs, power needs, or cost saving measures.

I just spun my wheels for the past hour trying to look up fuel economy ratings for similar vehicles offered in the US, NZ, AU, and EU. Sadly, for some vehicles, I can easily find fuel economy ratings for the US, but not other areas, or the other way around.

I had a similar question arise in a US Federal court case (where I became officially recognized as a Fuel Economy Expert) back in 2008. Back then, I was more easily able to look at the VW Jetta Diesel, Subaru Outback, and other global models to compare regional fuel economy ratings. What I found was the US versions ALWAYS got the worst fuel economy. European models faired 10-20% better than the US. AU/NZ models were rated at 20% to a whopping 70% better fuel economy. (Specifically, Volkswagen had their Blue Diamond Diesel engine that was getting the equivalent of 72 US MPG Down Under versus 42 MPG in the US in the Jetta!)

This begs the question; do NZ/AU versions get worse emissions, or do US versions leave a lot on the table??

Though I cannot verify this, a friend of mine spoke with a Toyota engineer that claimed they can get well over 200 MPG US in their Camry (in the lab), AND MEET EPA EMISSIONS STANDARDS OF MAXIMUM EMITTED EMISSIONS TOXINS! However, the EPA tells them what fuel delivery system they must use, that they have to use specified catalytic converters, what software limitations they must stay within.... All evidence suggests the EPA has mandated a maximum fuel economy capability that must be enforced by the ECU -- at least in the US.