HHO: Good, bad, or ugly?

[IamIan]

Originally Posted by ngrimm

Looking at this pdf
http://www.google.com/url?sa=t&rct=j...hh97-NKC-E4KMA
The diagram shows fuel being fed directly into the catalyst so the engine is able to remain in lean burn mode. Hence the reason for the catalyst in the first place.

Ahh ... now I see the difference ... Instead of a ICE purge cycle to get the unburned fuel hydrocarbons to the NOx catalyst , they are pumping unburned fuel directly from the gas tank into the cat.

Interesting.

So the catalyst functions the same concept / principles ... but they are applying / getting the unburned fuel hydrocarbons to it differently.

hmmm .... I wonder how difficult it would be to safely accomplish the same direct fuel pumping to my Gen-1 Insight NOx Cat.... then I to would never have to leave lean burn .... hmmmm... the safely thing will probably be a deal breaker....

Although I guess the other question is how much unburned fuel is being used? ... In this 'new' routing method they are getting 0% of the re-routed fuel energy in the ICE because it is all being bypassed to go directly to the cat ... where instead there is a % of the fuel energy content still being used in the purge cycle of Gen-1 Insight ... this suggests there is a break even point ... where the 0% of bypassed fuel energy used in the ICE is a bigger waste of fuel than the lower % ICE efficiency of the purge cycle ... I wonder where that break even point is.

Sadly neither that article or others I've yet found indicate the rate of bypassed unburned fuel going to the cat ... ideally to know the break even point we would want to know that rate compared to the ICE fuel consumption rate at the same time.

[Ken Fry]

Originally Posted by IamIan

... this suggests there is a break even point ... where the 0% of bypassed fuel energy used in the ICE is a bigger waste of fuel than the lower % ICE efficiency of the purge cycle ... I wonder where that break even point is.

I've been casually following this, and it is really gratifying to see the thread veer from fantasy land not just back to reality, but to such an in-depth discussion of combustion control.

I'd have to think that the difference in actual fuel consumption would be hard to measure even at a constant speed lab dyno test. My guess is that, in both cases, the maximum unburned HC going into the converter is no more than 1% of the fuel burned in the cylinder. Generally 1% excess HC seems to be about the limit of what a converter can tolerate.

But I am speaking from relative ignorance... I'm posting mainly to say thanks for the good discussion.

[user removed]

Not to offend anyone here but the idea of injecting fuel directly into a catalytic converter to me is disgusting. I like this much better. The reason I use the term disgusting dates back 40 years to the first emission controls and the continuous additions of many "bandaids" to the problem instead of "fixing" the problem itself.

Please do not think of this post as any kind of flame, it is not intended to be that. I just want to see the core issues addressed, instead of squirting fuel into a catalyst.

Make the combustion cleaner and eliminate the catalyst altogether. Then you don't have to worry about some thief with a battery powered chop saw stealing the platinum out of your car!

Transonic Combustion | Ultra-high Efficiency Fuel Injection Systems

I think this system holds a lot of promise, but I haven't bought any of their stock.

Yet.

regards
Mech

[Ken Fry]

Originally Posted by Old Mechanic

Not to offend anyone here but the idea of injecting fuel directly into a catalytic converter to me is disgusting.

Thems is mighty strong words, pardner.

I agree that it would be nice to avoid the use of a catalytic converter, but the three-way catalyst was the start of a group of technologies that have permitted specific output levels from family sedan engines that are much higher than we used to get from pretty exotic sports car engines. Prior to emissions controls, we thought of 60 hp per liter as being quite good for a sports car, and put up with 10% of the fuel going out the tailpipe unburned. Now essentially nothing other than water and CO2 comes out the tailpipe, and we get 75 HP per liter from family sedans. None of the old engines were more than 25% efficient at peak, but now the Prius is 37%.

While it seems counterproductive to inject HC into the converter, that is essentially what we have been doing for a long time with spark ignition engines. Injection typically dithers between 1% too lean and 1% too rich in SI engines: whether it actually passes through the cylinder makes little difference. I'd say it's an unfortunate fact of life, or perhaps ironic, rather than disgusting.

But I agree, the Transonic system sounds pretty good.

[fastegg]

I agree... while we're at it, Ive got a broken LCD-LED tv at home... maybe i could drain out the Liquid crystal, mix it with the oil and WALLA !!! more HP and better fuel economy... and while we're on the recycling band wagon, we could put the used LED's in a tube to mix drops with fuel and whadya known, it morphs the plasma into some kind of semi-conductor which in turn gets, you guessed it, more HP and better fuel economy.... Now the icing on the cake is in the fancy youtube video with little mechano motor running with a couple of multi meters showing a good turn of volts and amps. Sweet, now we're ready to list the whole shooting match on ebay, complete with claims to cut your fuel consumption by 50%..... Sit back and watch the profits roll in....
Its hard being green, but someone's gotta do it...

[oil pan 4]

Originally Posted by Old Mechanic

the first emission controls and the continuous additions of many "bandaids" to the problem instead of "fixing" the problem itself.

Sounds a lot like some of the latest diesel emissions technology out there.
Exhaust fluid!? WTF?
Shooting fuel onto the DPF filter to burn off the soot!? (great for fuel milage )
EGR! Just when it starts to disappear on gas engines it reappears on diesels.

[oil pan 4]

Originally Posted by IamIan

then I to would never have to leave lean burn .... hmmmm....

The problem with staying in lean burn under heavier load is it can cause pre-ignition and possibly burn exhaust valves.
Spending much time under load in 13.2 and/or 15.7 to 1 air fuel ratios burns exhaust valves.
13.2:1 creates the most torque and highest EGTs, but EGTs and NOx peak at 15.7:1.
Anything much leaner than 16:1-17:1 (around where honda lean burn is) burns at a good temperature but doesn't create much power, getting up to speed on the highway, passing and going up mountians could become a problem.

[fastegg]

Originally Posted by Ken Fry

Thems is mighty strong words, pardner.

I agree that it would be nice to avoid the use of a catalytic converter, but the three-way catalyst was the start of a group of technologies that have permitted specific output levels from family sedan engines that are much higher than we used to get from pretty exotic sports car engines. Prior to emissions controls, we thought of 60 hp per liter as being quite good for a sports car, and put up with 10% of the fuel going out the tailpipe unburned. Now essentially nothing other than water and CO2 comes out the tailpipe, and we get 75 HP per liter from family sedans. None of the old engines were more than 25% efficient at peak, but now the Prius is 37%.

While it seems counterproductive to inject HC into the converter, that is essentially what we have been doing for a long time with spark ignition engines. Injection typically dithers between 1% too lean and 1% too rich in SI engines: whether it actually passes through the cylinder makes little difference. I'd say it's an unfortunate fact of life, or perhaps ironic, rather than disgusting.

But I agree, the Transonic system sounds pretty good.

Ken Fry.... I was just admiring your vehicle... what is it ? Have you got a written run down of the story and specs ?.... and while i'm on a role, have you got some pictures you could email me ?.... I reckon it looks soooo cool....
fastegg@tpg.com.au

[IamIan]

Originally Posted by oil pan 4

Anything much leaner than 16:1-17:1 (around where honda lean burn is) burns at a good temperature but doesn't create much power, getting up to speed on the highway, passing and going up mountians could become a problem.

side note: ... 12 year old Honda Insight Lean Burn is significantly above 17:1 ... independently measured peaks at up to 25.8:1 ... and regular operation up to 22:1 is common.


Efficiency is a higher importance to me than Power ... just my personal preference... the Peak Torque or Peak Power Points of the ICE are way down my personal list compared to the Peak Energy Efficiency points.

Loads always vary in the real world ... and their are a number of solutions to that ... over size the engine ... have a more variable engine design so the same engine can choose to sacrifice some engine efficiency for more power when needed ... HEV systems ... etc...

The insight's design is a good example of using multiple approaches to give a variable system that can go from a very efficient cruising condition to trade off some efficiency for more power as needed ... the IMA motor is able to produce ~40% of the system's drive torque under 2,000 RPMs ... AFR varies from as rich as 12.5:1 to 25.8:1 and Ignition timing varying from -20.5 to +46.5 ... V-tech engages and disengages ... etc ... because on the relative flat of the highway running the system like when you need power to climb a mountain is just wasting fuel.

The occasional ICE purge events ( AFR 13.5:1 ) in the Insight while running in LB are to reduce the toxicity of the emissions produced during LB ... has nothing to do with needing more power ... my comment you referenced/quoted was referring to the potential alternative method of dealing with the emission toxicity without leaving the more efficient ICE LB operating condition when conditions do not need the additional power.

[user removed]

Originally Posted by Ken Fry

Thems is mighty strong words, pardner.

I agree that it would be nice to avoid the use of a catalytic converter, but the three-way catalyst was the start of a group of technologies that have permitted specific output levels from family sedan engines that are much higher than we used to get from pretty exotic sports car engines. Prior to emissions controls, we thought of 60 hp per liter as being quite good for a sports car, and put up with 10% of the fuel going out the tailpipe unburned. Now essentially nothing other than water and CO2 comes out the tailpipe, and we get 75 HP per liter from family sedans. None of the old engines were more than 25% efficient at peak, but now the Prius is 37%.

While it seems counterproductive to inject HC into the converter, that is essentially what we have been doing for a long time with spark ignition engines. Injection typically dithers between 1% too lean and 1% too rich in SI engines: whether it actually passes through the cylinder makes little difference. I'd say it's an unfortunate fact of life, or perhaps ironic, rather than disgusting.

But I agree, the Transonic system sounds pretty good.

Ken, I couldn't agree more about the advent of the 3 way Cat. In the Nissan Z car it was the 1981 model. They raised the compression and began the pathway back to performance. Engines could be tuned for power and the cat would clean up the emissions. FI was working at 40 PSI regulated.

Now 30 years later it's time for the next "significant' jump in emissions technology. FI in some cars today is approaching 200 atmospheres pressure. Computer controls, only a dream in 1981 allow multiple injections at multiple points in the combustion stroke. In 1981 the injected fuel first had to get past the intake valve. Today the injected fuel cools the combustion chamber temps and can actually provide the means for significantly higher compression ratios, which is the source of more power (not the only source but the principle one). Precise control of the cam timing can eliminate throttle plate restrictions in many cases.

Precision control of transmission shift points, as well as the dual clutch 6 and higher speed transmissions allow more low speed higher load operation.
The wife's Sorento has a 2.4 liter 4 cylinder engine, producing 191 HP on regular pump gas. Combined with a 6 speed dual clutch transmission in a 3800 SUV, you have an EPA rating of 32 MPG highway.

The Mazda SKYactive seems to go a step further. The previously linked Chiron free piston engine, which has thermal efficiencies as high as any currently produced IC engine regardless of size, could produce fuel economy of 50 MPG in the same vehicle. Add to that an operational tactic of run at best bsfc or not run, and a capacitive regeneration system and you can only guess at the mileage. The EPA calculated an 80% improvement due to power train advancements in 2006.

Manufacturers today, in my opinion do not want to see leaps in progress that would make last years models obsolete overnight. The resulting economic disaster in the used car market would be unprecedented if a quantum leap in technology was incorporated today. The question is can we truly afford to wait until THEY decide the technology should be made available, or should we just build the damn thing our self.

regards
Mech