Cruise control cylinder cut.
 

sorry for the alliteration...

my ideal idea is a 2 cylinder shut-off when cruise control is activated, coupled with a hydrogen generator to make up for lost power. any ideas? i understand that the hydrogen generators are not efficient, and i'm really not worried about the battery draining. the hydrogen would simply complement the combustion, and help prevent detonation from an extremely lean situation.

for this i understand i need proper tuning. i can handle that.

my questions basically lie with the wiring and set-up as a whole. i want it to be one fluid step. i.e.: setting my cruise control automatically cuts fuel to two cylinders, turns on the hydrogen generator, and corrects the voltage(s) sent to the ecu. i suppose this could even be done with water injection, but if hydrogen supplies extra power, i think that's the better route.

with this set-up, i believe i (and anyone else) can acheive 60+% highway mpg (or l/100km) improvements, even taking into account the extra load put on the engine. if modern cars only need in the realm of 50hp (or even less) to maintain highway speed, why are we even using all this extra power??

comments/ideas/opinions please.

do a search for cutting cylenders, others on here have tried it, explaned very well as to what they did, and why it didn't work.
a number of vehicles that are for sale do cut cylenders, but they do so with very carful enginering, mostly useing a very complex head and rocker arm arangement.

If you have a fuel injector on each cylinder you could just have a relay that cuts the grounds to two of the cylinders when you hit the cruise button.

I wouldn't bother with the hydrogen, I've always shown worse results with it and the fuel cutting should be an independant experiment from hyrdrogen anyway.

I'm also not sure what you mean by correcting voltages, you shouldn't need to do anything else, fuel calculation will remain the same and be fine because you still want to inject the same amount of fuel for the same amount of sucked air in the intake per cylinder (you're going to be pumping air through the 'dead' cylinders). The only issue I can see is possibly with the O2 sensor reading wrong since half the volume of air will now be unburnt atmosphere.

The car companies that do this now (Dodge and Chevy I think?) go one step further and have sophisticated ways to collapse the lifter on those cylinders and prevent them from sucking in air and expelling unburnt air to the 'dead' cylinders. This still isn't ideal though because the clyinder is still sucking against a closed chamber and building vacuum (which is robbing efficiency). There was another thread where a guy turned his car off at the top of a hill and saw how far it'd coast in neutral and then did the same experiment again but left the car in gear (so the car was forced to spin the engine) and it went much less of a distance, engines are a major drag when not combusting.

One thought a friend of mine had was maybe have a seperate valve/chamber on each cylinder that opens when the cylinders are 'dead' and would equalize pressure to them. That is say you build a valve into the spark plug or something and hook it to the other cylinder you plan to kill, they would have 0 pumping losses because when the one pulled down the other would be pushing up, they'd just be pushing the same air back and forth. I couldn't really picture what he meant when he said building a valve into a spark plug, the way I'd do it is drill a new valve into the head away from the camshafts (so out the side on DOHC car) and actuate it with an electromagnet. Electromagnets can't pulse fast enough to be fully electronic valves, but you're going to turn this one and off for minutes at a time and this will work perfect for this.

Either way, make sure to cut matched cylinders (that is 1 and 3 or 2 and 4), because other wise I would it would be too lopey and put too much stress on the crank.

And have proven incredibly reliable and effective...well they haven't blown up but they're not as economical as an import engine of similar displacement. less power and less mileage...still. go GM and chrysler.:thumbdown:

severedgein -

Everything I've read on this website points to 4-bangers being bad candidates for cylinder deactivation *unless* they are horizontally opposed boxer engines, as in Subarus, VW Beetles, and Porsches. What engine are you planning on using?

If I were you, I would spend time reading the newsletters that are here :

Hydrogen Boost Newsletters - Research and Development Reports
https://www.hydrogen-boost.com/newsletter.html

In this newsletter example below, the developer admits that the hydrogen booster has "negative FE" zones, which is one reason why I think he is an honest broker :

Diesel Dynamometer Testing Analysis - September 2007
https://www.hydrogen-boost.com/September%202007.html
I'm NOT suggesting that you buy this one because it costs a lot of $$, but there is a lot of practical information in the newsletters.

CarloSW2

i have a H22a1 engine. i could also engage VTEC to allow better air flow to the cylinders.

but yes, my main concern is the o2 sensor reading extremely lean. i'll work out the kinks as i go, but i'd like to at least try this.

Have those of you with VTEC ever considered a radical cam grind over disabling cylinders?

You could setup the cam switch so when it activated it left the intake valves open for about 50-66% of the compression stroke. That would make it where you can floor the engine to reduce pumping losses working against a vacuum on the freeway or just under floored and get an FE increase. It's similar to miller cycle except way more radical and geared towards fuel economy since you don't have the supercharger..

Just an idea. You'd have to go standalone to get that to work right and if you want a perfect setup you need to try different durations until you get your engine putting out just enough power to attain the speed you want to always cruise at.

so basically, i'd have my throttle wide open on the highway and 60-65 would just be my top speed due to the powerband?

Yep- I hope you live in Kansas because if/when you come to a hill, your top speed might go down to 45 :D

Unless you go back to using all cylinders or downshift and rev it more.

Exactly, and when you need more power you switch te VTEC back over to the original cam setting and it drives like normal again.

Well here goes. I think your cylinder deactivated cruising mileage gain will be at best only a little more than the best that can be achieved by pulse and glide near the speed you want to drive. If you are driving 60 mph this will often be about 10-15%. 10% gain is about all the big factories claim for mileage gain with cylinder deactivation.

When I was in college I simulated extreme compression and late valve closing in a simple basic program. Using a 15:1 compression ratio and closing the intake valve at about 85-90 degrees before top dead center resulted in the same peak cylinder temperatures and gained about 3% in thermodynamic efficiency in the simulation. Assuming a 25 hp load this resulted in about a theoretical 10% mileage increase.

Both ideas are valid but the gains are incremental. If you look at a PV diagram, Pressure vs Volume plot of a working cylinder what you are trying to recover is often the tail end of the plot and there really is a small amount of work that can be recovered in that area.

I have driven vehicles with cylinders deactivated and I have driven the old Ford Turbo-coupe with the cam retarded three teeth. A person can do these things. The retarded cam experiment would have been more valid with a twin cam engine or a special grind cam. One can do these things but the gains are not as big as you expect when you work for a day or so to set them up.

Higher compression is good. Higher compression with a little extra duration before intake valve closing is better. Combine that with Somender Singh grooves might even be better.

If you want to deactivate by shutting off injectors I think you need to move the O2 sensor to a location where it is not affected by the excess air. That would involve a little fancy work in the exhaust system.

I think I am kind of pushing the practical limit on simple engine experiments. I am thinking of returning to where I was going before I got involved with my Saturn. If you really want to go a long way on a bit of gasoline you need excellent aerodynamics and a plug in hybrid. Maybe that is cheating but that is where I think it is going to end up. If you start with an efficient car such as a Honda, Saturn, or Corolla there is not a lot of low hanging fruit left to pick from those engines.

Just some rambling thoughts as I read thorugh this thread.

Retarding cam timing is an interesting concept, I've heard of advancing the cam timing to get more low rpm torque for better mpg with cars that have a high geared trans, but I've never heard or retarding the cam timing.

So how did the engine run after retarding the cam timing that much? Did it sacrifice any drivability?

Without changing compression ratio the advanced profile cams are an effort at increasing cylinder pressure. I ran one with dismal results. Opening an intake valve too soon can allow exhaust gasses into the intake. Hence the ratty idle. A problem I have experienced with this type of cam is increased heat at the intake valve leading to coked up intake ports. For the optimum benefit of the advanced profile the engine should be ran at higher load. These cams were sometimes called RV (Recreational Vehicle) grinds in the first oil crisis. They can help but at very light load they offer little gain. I ran this kind of cam in a v-8 I drove for 5,000 miles on 4 cylinders.

Drivability was very poor at three teeth retarded. I usually ran one tooth retarded. Retarding the cam opened the exhaust later to try to get a bit more work out of the gases before the exhaust opened. Even two teeth retarded exaggerated turbo lag to unacceptable levels. I could play with turbo boost level to make up for the lower volume trapped in the cylinder.

Naturally aspirated you really need the combination of higher compression ratio and late intake closing which is primarily what Miller cycle or Atkinson cycle is. Here are some links that explain it pretty well.

https://en.wikipedia.org/wiki/Miller_cycle

https://en.wikipedia.org/wiki/Atkinson_cycle

What you really need is an engine with some sort of VVT technology. That way you can have the best of both.

WARNING: Perhaps I should have mentioned that one must take care not to run a valve into a piston when doing things like this.