Another Kill Switch Idea
 

So I was wondering if this was possible and what it would take to do it...

I was thinking about having a kill switch (either a button or put it into neutral, more on that in the next paragraph), which will kill all, but one of the cylinders. When at a light I can hit the switch, which will kill 3 cylinders, but leave one on. When the light turns green, the other 3 cylinders will come on when I step on the gas, either all at once, or individually as needed (like a certain RPM count turns another one on, then the next, then the last). If I can make it to my destination without turning the other cylinders on then great, if not then I have the power of the cylinders to get me up to speed, but they won't be used if I don't need them.

For the neutral kill switch, I am thinking it would need at least two inputs. The first is obviously the transmission in neutral, but the second is RPM speed. If I am at speed and RPMs are say 1500, then it will not kill the engine, but at lets say 900 or less RPMs then it will work.

My question is: is this possible?, how do I do it?, and would it save me fuel in the long run (i.e. does the load of one cylinder powering the whole car without the "help" of the other 3 cylinders negate the savings of the other 3 cylinders being off?

Thanks for your help and insight!
Jeff

I'm not the knowledgeable, experienced mechanic by any stretch of the imagination, so this is just idle brainstorming because I like your thinking.

First, I guess you'd want to be killing the injectors instead of the spark - otherwise you'd be pumping raw fuel through the engine & out the exhaust.

Second, I kinda doubt it would even keep running on only one cylinder. When my 4-cylinder Swift had 2 dead cylinders, it barely ran - and when the mechanic pulled the power to the injector to either of the "live" cylinders, it would die almost immediately.

Third, I suspect you'd have to figure out some way to hold the valves open on the deactivated cylinders, or else the one remaining running cylinder would just be powering 3 "air compressors" doing nothing but sapping a bunch of energy. It's far beyond me to even imagine how the valve holding open thing would work, but I think the cars that actually can deactivate cylinders do something like that.

Neat idea, but not practical. Modern cars attempt maintain a set rpm while idling, and deactivating cylinders that are normally running will just make for a rough idle and either not save any fuel, or such a minuscule amount as to not be worth the hassle and rough idle.

You will also get misfire codes since the computer thinks the engine is running, but isn't detecting combustion events.

In addition to ^, it won't run unless it also gets a heavier flywheel.

You have several issues.

First, if the valves are still active on the de-actived cylinders, then you're going to have pretty much the same friction & pumping work to overcome as you did when firing on all cylinders. You might gain a little efficiency by running the one cylinder at a high load factor, but probably not much.

Second, if you didn't deactivate the valves, it's going to wreak havoc on the AFR control because the O2 sensor will see all the fresh air from the non-firing cylinders and massively over-fuel the firing cylinders.

Third is the mechanical balancing issue. Like Frank said, a single cylinder engine needs a massive flywheel to have enough retained momentum to complete the compression stroke.

Ok so it sounds like I came up with another unicorn idea. :) What if I ran the same setup, but killed all the cylinders. The 'key' to reactivate them would either be putting it in 'D' or putting in in 'D' and pressing the accelerator. Then they would all go back on like normal. Or is this no different then a normal kill switch?

Would it need a heavier flywheel if it only ran one cylinder in neutral and all of them in drive?

Going back to wmjinman's point, how do the modern deactivated engines hold the valves open? Computer tells it to stay open, but what actually stops gravity from holding them down? Also do these vehicles have a camshaft? With yhe ability to stop the valve action I would think the nudge (excuse the improper name) on the shaft would need to be out of the way, so it doesn't force the valve down.

Thanks!
Jeff

Pop the hood, start it, pull injector or plug wires until there is one cylinder left or it quits, whichever occurs first.

Google "cylinder deactivation". There's quite a bit of info out there...even wikipedia:
Variable displacement - Wikipedia, the free encyclopedia

And actually you need to keep the valves closed--not open.

And with an automatic kill switch remember that the kill switch is only halh the picture-- you still need to restart the engine. With an automatic tranny you can't bump start so that means you would have to use the starter to restart...which has other issues like wearing out the starter and draining the battery down.

OK, so valves closed, good to know (and makes sense).

That is why I wanted to keep a cylinder on, to keep the ICE on and not have to restart it at every light I stop at. Unfortunately, it looks like that won't work.

I wouldn't even know where to begin with that! I know about cars, in theory, but in practice I am a little more amateur. That's what friends are for though! ;)

I am also still wondering if it would need a heavier flywheel for one cylinder if I only have one cylinder on in neutral?

Thanks!

Yeah, I think it would still need the heavier flywheel. Maybe more realistic to leave TWO cylinders running & only kill the other two. May get away with keeping the stock flywheel that way. And I know my Swift would run - barely - on 2 of the 4 cylinders, but not one.

As far as "de-activating" the valves, I dunno. . . seems the cam would need to be moved away (but that would probably mess up the cam settings, etc.) or else somehow the valves moved away from the cam - - - or some sort of adjustable spacer between the valves & the cam. Maybe adjusted "down" so the cam doesn't activate the valves when the cylinders are turned off, and then "extended" again to start working again. Maybe something like a "lifter" in the old pushrod engines that has some sort of valve to allow it to "pump up" when it's time to work the valves, and "drained" when it's time to shut down the cylinders. I'd think this would have to be part of the original design of the engine - don't know how to try to retrofit an existing engine to do it.

I can't help but wondering if this would have any advantage over the simple kill switches that just shut down the fuel to the whole engine? If you wanted it to keep running, say, because it's an automatic you can't "bump-start", maybe just coast in neutral? I guess sitting at a red light for a couple minutes with the engine idling would be tedious - but even those of us with manual boxes still have to use the starter in that case.

Many years ago, my wife's 4 cylinder Gemini (Isuzu) snapped the camshaft in half so that only the front two cylinder's valves worked.
It idled OK and drove (just) on the flat, but couldn't fight it's way up any sort of hill.

To give you an idea of how big flywheels need to be for single cylinder engines, here you go:

http://sphotos-b.xx.fbcdn.net/hphoto...03541056_n.jpg

I got to see one of these run in person once. Quite the sight. Each flywheel is about 6 ft in diameter.

First, thanks for the pic, now I get what you mean by HUGE!
Second, I don't see that as a problem, I think that will fit in my 'lil Corolla! HAHAHA:D
Third, what would that be for? A train of some sort?

Thanks for the help guys, it looks like I won't be able to do this project, at least not until I decide to design/build my own engine! :)

The one I saw was used to generate 440v electricity for a remote grain elevator in the 1920's. BTW, despite weighing several tons, it only put out 125 hp. Shows you how far engine technology has come! I have an antique engine in my garage that I'm working on restoring that's form 1927. It's like 350 lbs and puts out 1.5 hp.

To be fair, a flywheel for a one cyl. B&S will fit on your salad plate; one from a Honda Cub will fit in a cereal bowl.

I think Diesel Dave is joking with that picture. Look at all the single cylinder lawn mowers, generators, and such. They undoubtedly have heavier flywheels in relation to their size, but not comical proportions like in this picture.

I'm not sure if that's a steam engine or not, but it made me think of steam (I kinda have a "thing" for steam). But with pehaps not much more effort than your cylinder deactivation idea, a "steam-o-lene" design like Bruce Crower of Crower Cams came up with intrigues me.

What he does is has a special cam with additional lobes (convenient he's a cam manufacturer, huh?) that open the exhaust valves again, making it a 6-stroke engine instead of 4-stroke. Then there's an injector that squirts some water in at the start of the 5th stroke, which is the second power stroke - a STEAM power stroke.

So the engine goes like this:

> 1st stroke: Intake - intake valves open, piston moves down drawing in intake "charge"
> 2nd stroke: Compression - all valves closed piston moves up, compressing charge
> 3rd stroke: Power - all valves closed spark plug fires, fuel burn drives piston down
> 4th stroke: Exhaust - exhaust valves open, piston moves up, pumping exhaust out.

That's where a "regular" engine goes back to stroke 1, "intake". But in Crower's design, you get:

> 5th stroke: steam power - water is injected near TDC and heat causes steam, driving piston down again
> 6th stroke: steam exhaust - exhaust valve opens again due to 2nd cam lobe, piston moves up, pumping steam out.

And then you go back to stroke 1, Intake.

We always talk about all the waste heat in an internal combusion engine. This scheme uses the heat to make steam and more power. Cooling system could possibly be eliminated altogether. Imagine the "aero" possibilities if you didn't have a radiator you needed to get air to all the time!!!

Bruce calculated the potential efficiency improvement with his design, and it was substantial. Just going off my poor memory, it was something like 25% improvement in gas engines and even more - I wanna say 40% - in diesels!!! Patent pending, I believe...

It's possible I may have overstated things a wee bit :D

Obviously you wouldn't need something nearly that large, but it does illustrate the point.

BTW, it's actually not a steam engine, but rather one of the early diesels ("oil engines"). Given we we coming out of hte steam era, most early internal combustion engines bear a strong resemblence to steam engines. I've even seen one or two old antique gas hit and miss engines that we converted from steam engines.

That is an awesome idea! I was thinking about the theory of a 6 stroke engine like that last week, but I didn't think about steam! I wonder if there is a way to capture the steam, let it cool down to a liquid again (maybe at that point you would still need a radiator, or at least an intercooler) and then inject it again. You might have to put something like anti-freeze in for it to not rust anything and to keep the water from condensating out just like a 'normal' cooling system. Would the engine be hot enough to make the anti-freeze turn into steam with the water though? Also, I wonder if this would work with a turbo, where the steam would turn the turbo turbine rather than exhaust gases (or maybe both?).

Not sure the answers to all those questions, but they are good questions. The thing has been discussed on here before, but I'm not sure where. Some were claiming "unicorn" and citing no further word since the article in Popular Mechanix describing it as evidence it didn't really work.

As I recall, he anticipated needing a variable volume water injector to match the amount of heat the engine was producing at the moment, since that isn't a static number. He tested it on an old one cylinder diesel engine he had, because one cylinder is a lot simpler to test something like that on, and because diesels tend to be stouter due to their high compression, etc. I think he used the regular injector for the diesel to squirt the water in & drilled & tapped a new hole for a spark plug to fire the gas, then just put a carburetor in the intake path.

He fiddled around with it until he got it running really good, sent off for a patent, and, if I remember right, once the patent was in place, was going to try to find someone to sell the manufaturing rights to.

Seems like they did mention whether they should try to condense & recirculate the water (which would require a much more involved "exhaust system" though, right?), or rely on people being smart enough and reliable enough to know to fill the water tank as well as the gas tank. And of course, the "anti-freeze question" for those of us who get sub-freezing winters was brought up, too.

The discussion on here about why they aren't on the road yet (this article was several years ago, now) ranged from some evil oil company buying the "rights" & then "burying" it to having lubrication problems with the steam (steam engines have different - and in many ways, more severe - lubrication challenges), to having metal fatigue problems from the wider range of temperature fluctuations with it getting heated by burning gas & then cooled by vaporizing water dozens of times a second.

But who knows? In this age of "space age" materials and engineering, I can't imagine those problems being insurmountable. Personally, I thought it was one of the most brilliant ideas I'd ever seen!!
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