Basics of Pcv vacuum for Fuel vaporizer

[bradlington]

I see many are promoting vaporizers and have used myself with success.

One thing to note about the average user-- the vacuum is inversely proportional to the opening of the butterfly .
This being noted :
No foot on accelerator equates to max Vacuum.
Full acceleration-foot flat equates to low vacuum.

This means max vapor is being sucked in while idle and lowest when full throttle.

Has anyone use vapor in only cruise mode - manual or other - or made a way to inversely correct the relationship .

One could use a variable pump that can be controlled by an arduino or similar to monitor the vacuum.

Please share your ideas.
Thanks in advance
Brad

[oil pan 4]

Actually no you get the hugest vaccum when cruising down the road.
At idle typically you should expect to see around 13 to 15 inches of Hg. Cruising down the road with a light engine load you can see 18 to 22 inches of Hg.
Letting off the gas while rolling along can give over 25 inches of Hg.

Otherwise I'm pretty sure fuel vaporizers don't work.

[bradlington]

I have since installed a vacuum gauge to aid in my testing - Max vacuum is at idle and lowest is at WOT .
This is for my vehicle being a Subaru boxer ej251 non turbo

[MeteorGray]

That is typically what I see: max vacuum at idle of maybe 18 inches, zero at WOT, maybe 10 or so on the highway. Of course, getting off the throttle and coasting down can get it to maybe 25 inches or so.

This brings back fond memories of my long, long ago youth, when cars had vacuum-motivated windshield wipers. Typical scene: you're moving along at 60 mph on a two-lane road in a rain and come up to a guy moving at 50. So, you floor the go-peddle to pass him, and the windshield wipers freeze in place because there's no vacuum to operate them.

Passing blind on two-lane roads was a hoot.

[Ecky]

What is the function of a fuel vaporizer? Is this to add fuel to the air charge before the injectors fire? I've been doing a lot of engine tuning lately and it seems to me this would wreak havoc on AFR.

At high load most ECUs go into open loop, meaning vaporized fuel would not be accounted for and an engine would go very rich (wasting fuel). Ideally you wouldn't have any added fuel at high load.

vacuum is highest at DFCO, when the engine wants zero fuel, and a system that's adding fuel at this time is just dumping it out the exhaust.

If fuel is added proportional to vacuum, it would make it difficult for an ECU to apply fuel trims at part throttle low load. Usually, different conditions cause a fixed (e.g. -3%, +5%) difference in fueling needs, be it from temperature, humidity, w/e, and an ECU will apply a fixed trim to correct this - except in open loop zones of the fuel tables. If added fuel is variable with vacuum, AFR would be all over the place while driving.

What is the function of a fuel vaporizer and how is it supposed to bring benefits?

[bradlington]

A constant supply of vaporized fuel will reduce the injectors from staying open each session .
After install one should reset the ECU and most learning ECU's have a certain period where data is gathered and stored -thereafter the ECU is then in control under closed loop to provide the mapping under certain conditions.

The AFR is all over the place when people drive anyway - I have an additional wide band in my exhaust and I watch the AFR like a hawk .

One can use PCV but I would say from only my experience is that one ideally wants to add a constant flow of vapor in small increments via the throttle body .The ideal start would be that required at the the first step of IDLE off .

By doing so one can record the pulse width of injectors to make the decision to increase or not .Older carb vehicles were easier to do this to and modern ECU's are a lot more difficult to manipulate under closed conditions.

The airbox beginning is not always a good thing as on some vehicles there are additional inputs /outputs being the PCV system that shares the airbox .

ECU manipulation would help if that is at your disposal and you know what you are doing .

At the end of the day fuel in a vapor state is more efficient period.
Injectors spray droplets that are still many times larger than cracked fuel .

Perhaps the burning question (no pun ) is why did the motor industry force ECU systems .Perhaps it was not global warming but too many people getting close to amazing mileages per liter of fuel .

I have tried it on my vehicle and run a small genset on vapor and it works .

[Ecky]

ECUs still follow maps and tables, and make certain assumptions about the environment. The learning can only go so far - basically some table values can be modified, but it's not true "learning". It's only as clever and the engineer who designed the tables to be modified.

Regardless, ECUs have some tremendous advantages over analog systems. Some examples:

I can't speak for all engines, but for at least 30 years Honda has had greater than 99% efficient combustion of fuel, suggesting there is no issue with fuel atomization to be solved.

In my engine, there are some areas where very clever intake and exhaust design have increased the volumetric efficiency to over 110%. An ECU can be programmed to retard timing and add extra fuel locally to these specific regions, something which cannot be done (to my knowledge) in an analog system which follows linear or exponential curves. Using a carburetor on my engine would result in needing to run very rich over areas of the curve to compensate for zones of 100%+ volumetric efficiency, and needing to run excessively retarded timing over large areas of the rev range so that it's not too advanced in areas of high VE. Fueling doesn't always follow vacuum or curves, and there's a lot of use of having sensors that can give combustion exactly what it needs to be most efficient in every scenario.

I'm sure carburetors could be used with some very basic implementations of things like variable valve timing and variable valve lift, but I haven't the faintest idea how one would compensate for changes that result from having multiple cam profiles and 50+ degrees of intake and/or exhaust cam phasing. These systems boost both engine efficiency and power.

In many modern engines, fuel is intentionally added late during certain parts of the load/RPM map to ensure it doesn't spread homogeneously throughout the charge in the cylinder, but instead is locally rich around the spark plug when it fires. This rich zone allows the flame front to spread more quickly, leading to increased combustion speed. When combustion happens more quickly, ignition timing can happen later, meaning less negative work is being done against the rising piston. This allows engines to be lighter, more powerful and more efficient. You can read about some of these things here:

https://jalopnik.com/heres-how-toyot...ere-1824090404

I have a car in my driveway which can cruise at greater than 100mpg on the highway in a way that is repeatable, measurable, and understood. Fuel is already burnt completely, and electronic engine controls have increased thermal efficiency of gasoline engines from the 20's as seen in carburetor days to greater than 40% in some cases. In a well designed engine, I could see uncounted, vaporized homogeneous fuel/air charges being added in an uncontrolled manor only reducing efficiency. This may not apply to older designs, granted, but I'm highly skeptical of this showing positive effects on anything made in the last 10 years.

~

So, all of that said, and as skeptical as I am, I would love to see this work. Do you have any data on what has worked and what hasn't? Any idea on how and why?

[Xist]

My understanding is that the primary function of fuel vaporizers is to generate profit for the manufacturer.

[bradlington]

From your words you have already answered some of the questions , of which I still have many .
One has to ask why the early vehicles had gear shift timing that was adjustable by the driver on the fly .Same principle was used with aircraft - boost and cruise control.

The same principle has been used by some innovators tinkering with vapor and other methods to adjust by fuzzy human logic for efficiency .
The vacuum negative feedback resulted in being able to drive without the driver having to manually adjust - this made sense for demand but lead to the decades of cloak and dagger by manufacturers on how they do things and why.

I have one shortfall in that my vehicle is 1999 /2000 - sold as 2001 but the ECU is a closed shop in terms of people that have truly reverse engineered it . Over and above this the ECU does not spit out mpg in real time so my notes ,recordings and long term notes would not satisfy any scrutiny .
Here is what I think and only my interpretation and limited understanding :
Long term aims to move the industry away from the user ,home experimenter from gaining 100 knowledge of the inner workings of any ECU design .

Having said this going to Fuel injection and then direct injection showed that the industry was in a race to get the beneficial acceleration scores closer to public demand .

Going back to the manual timing and vapor - there is some lag in the sense that good vapor systems that are not pressurized for high speed delivery can have as an inherent part of the system .Slow acceleration and manual air control together with the vapor is key .
Looking at history ,the era when vapor carbs were becoming successful in delivery outstanding mpg figures, the change happened to follow the fuel injection design and OBD world adoption .

As far as mods go I can list them but they are for interest and I will not support any tech results or fugures. All I can say is never ending and ongoing projects .
List of my changes :
Exhaust -replaced original to free flow with Cowley straight through .
Cat delete-
HHO - hho supply to Throttle body intake controlled by manual PWM control . I am using KOH (Potassium Hydroxide as electrolyte)
AFR-On-board addition wide band O2 sensor for monitoring real time driving AFR .
Manifold Pressure gauge- for on-board driver monitoring.
Efie- Manual dual control for manifold offset
Fuel Heat exchange-My own design have not seen before on internet.This innovation is neater than the old school radiator or exhaust copper pipe versions .
PCV delete- Not common on boxer engines - filtered ports.
IAT -Internal air temp -Manual switch and offset adjustment .

Changes used already and to be added in near short term :
Water ultrasonic vaporizer
Fuel vaporizer - new design for heat cracking being made before adding .

One has to ask why vehicles in the early 1900's with such large bodies and weight still had really good efficiency out of the engine as far as BTU per liter of fuel .
Same family vehicle many decades later - third of the weight have same l/100 km consumption but the public are into believing that the efficiency is up high and non the wiser .
People in my country and many others spend a vast quantity of disposable income on cost of fuel to travel to and from work with no public transport to offset the choice .
My testing involved a 97 km round trip to work and back every day for over 10 years .
This was an amazing opportunity to do my testing and achieve some stats on my changes along the way .
Since being retrenched and without work ,my long distance testing has been somewhat limited but this has not stopped me trying to improve what I already have .
One day I think steam may make a return to direct drive type hybrids - instant power from zero up and no noise - may be a while though as this would mean industry would lose the fuel demand and every war runs on fuel .

In my changes along the way there were times when I thought "what have I done" am I going to blow my engine ,but for ten years travelling my vehicle was off the road for one day due to a clutch master slave repair which if I had the correct honing stones I could have negated this one .
Some figures since the first automobiles to current standings have not changed at the base line - same consumption city and highway - yet public truly believe modern cars are efficient .

[Ecky]

I'll give some thoughts on some other points in that case! Some will be opinion, some speculation.

Originally Posted by bradlington

One has to ask why the early vehicles had gear shift timing that was adjustable by the driver on the fly .Same principle was used with aircraft - boost and cruise control.

I personally like to have more control over variables; it's why I have an aftermarket ECU. If I were to take a guess at this, it's probably some combination of 1) Drivers can now basically control shift points entirely with the go pedal. Press it harder and the shift point moves higher, prioritizing acceleration. Also, 2) Most people either don't touch these things, or set them to very suboptimal settings. Engineers are pretty sure they're smarter than the average driver now, and have no issue with taking some things out of drivers' hands.

Originally Posted by bradlington

The same principle has been used by some innovators tinkering with vapor and other methods to adjust by fuzzy human logic for efficiency .
The vacuum negative feedback resulted in being able to drive without the driver having to manually adjust - this made sense for demand but lead to the decades of cloak and dagger by manufacturers on how they do things and why.

This made a lot of sense when systems were very basic/primitive, but for a long time cars did not have DFCO either - something vapor systems do not allow. ECUs can now call for the delivery of fuel as-needed, sometimes following very closely to how carbs did and other times very differently - as needed.

Originally Posted by bradlington

I have one shortfall in that my vehicle is 1999 /2000 - sold as 2001 but the ECU is a closed shop in terms of people that have truly reverse engineered it . Over and above this the ECU does not spit out mpg in real time so my notes ,recordings and long term notes would not satisfy any scrutiny .

On a 1999/2000 you could add an OBD II device like a Scan Gauge or UltraGauge. The forum is actually having a give-away for one of these right now. They do a pretty good job of approximating fuel.

If you want to get something more exact, you can pick up the parts to assemble an MPGuino very easily, which can count the fuel going through your injectors and is far more accurate when AFR varies, often coming to within 1%. I have one in my car and love it! It won't however, be able to account for fuel you're side-loading, such as with your vapor system or HHO. You would need to manually calculate fuel added this way and add that to your usage/expenses.

Originally Posted by bradlington

Here is what I think and only my interpretation and limited understanding :
Long term aims to move the industry away from the user ,home experimenter from gaining 100 knowledge of the inner workings of any ECU design .

Agreed. I believe it's actually federally illegal in the US to crack or replace an ECU in most cases, because it's "tampering with emissions systems". I can understand and appreciate emissions laws here (pollution and smog have improved dramatically in the last 40 years) while at the same time still bristling at a lack of my ability to change things.

Originally Posted by bradlington

Having said this going to Fuel injection and then direct injection showed that the industry was in a race to get the beneficial acceleration scores closer to public demand .

Going back to the manual timing and vapor - there is some lag in the sense that good vapor systems that are not pressurized for high speed delivery can have as an inherent part of the system .Slow acceleration and manual air control together with the vapor is key .
Looking at history ,the era when vapor carbs were becoming successful in delivery outstanding mpg figures, the change happened to follow the fuel injection design and OBD world adoption .

I've seen some vehicles with carbs that have some pretty good efficiency in narrow areas of the map, but it's hard for carbs to deliver the best of both worlds like electronic control can. With ECUs, there really isn't a whole lot left on the table in terms of tuning and improvement, unless you want to make some intentional sacrifices, such as increased pollution or engine longevity. There's no guesswork with it anymore.

Originally Posted by bradlington

As far as mods go I can list them but they are for interest and I will not support any tech results or fugures. All I can say is never ending and ongoing projects .
List of my changes :
Exhaust -replaced original to free flow with Cowley straight through .
Cat delete-
HHO - hho supply to Throttle body intake controlled by manual PWM control . I am using KOH (Potassium Hydroxide as electrolyte)
AFR-On-board addition wide band O2 sensor for monitoring real time driving AFR .
Manifold Pressure gauge- for on-board driver monitoring.
Efie- Manual dual control for manifold offset
Fuel Heat exchange-My own design have not seen before on internet.This innovation is neater than the old school radiator or exhaust copper pipe versions .
PCV delete- Not common on boxer engines - filtered ports.
IAT -Internal air temp -Manual switch and offset adjustment .

Changes used already and to be added in near short term :
Water ultrasonic vaporizer
Fuel vaporizer - new design for heat cracking being made before adding .

I recently read a peer-reviewed article showing positive benefits from the addition of hydrogen to intake charge. It showed faster combustion speeds than gasoline alone - which is good for both engine longevity and efficiency. However, effects were not really noticeable until around 6%. With hydrogen at atmospheric pressure, I'd estimate 6% hydrogen at atmospheric pressure to be around 360 liters per minute at high load, and perhaps 60-180 liters cruising. I can't see being able to do this without a pressurized tank.

Originally Posted by bradlington

One has to ask why vehicles in the early 1900's with such large bodies and weight still had really good efficiency out of the engine as far as BTU per liter of fuel .
Same family vehicle many decades later - third of the weight have same l/100 km consumption but the public are into believing that the efficiency is up high and non the wiser .

I don't know that this is actually true. The Ford Model T was mid-teens MPG, maybe ~15 average. However, this vehicle only weighed 900lbs and traveled no more than 40mph.

Starting in the late 30's and for decades after, the VW Beetle weighed in around 1650lbs. We still have these on the roads today and can see the fuel economy. Most people get around 23-25mpg, and they're not doing 65-70 on the highway.

In the 80's you could buy a Honda Civic which had a combined rating of ~26mpg, and weighed around 1800lbs. Maybe people did better than their EPA ratings, but not with the really equipped models.

The 88 Honda CRX HF was a 2 seater also weighing in around 1800lbs. It was rated for 44mpg combined, but this was, if I recall, without power steering or air conditioning.

Today you can buy a 4000lb 5 passenger car which will cruise at 45-50mpg at 65mpg with air conditioning, power steering, sound dampening, etc. etc., so I'm inclined to believe these fuel economy numbers from the past are revisionist history.

One thing that may really apply however was emissions. Gasoline used to have lead in it as a knock inhibitor, which allowed much higher compression ratios. Every point of compression is worth on average 2.5-3% fuel economy AND power, and I want to say some vehicles lost 4-5 points of compression when lead was removed. It's pretty clear to me why we shouldn't be blowing lead out of the tail pipes of hundreds of millions of vehicles, but also unfortunate we didn't have anything to replace it as an octane booster. My father claimed his 69 Camaro would get close to 30mpg on the highway (maybe 26-28mpg) at 55mph, and this was a pre-emissions vehicle, so no catalyst and a high compression ratio.