Home made variable displacement?

[nogard]

I try to do what I can to save gas. I'm reading more and more about these cars, mostly large V8's that have variable displacement engines, like the latest Cadillac Northstar, etc. I believe some of these idle and cruise like this to save gas.

I was wondering if the same thing could be done to the 3S-FE, mainly just for coasting and idling. I know this is just a 4 cylinder and isn't the same as the V8. I'm trying to recall from memory if the firing order is 1-3-4-2.

What if it ran on just 1 and 4, or 3 and 2. Would the spark and injector have to be shut off? And I would think a system to alternate between which cylinders where shut off would be good. So they all had an even workout.

[Jimnist]

Too much work to be honest. Even if you do find a way to shut off one cylinder and run on 3 (with a balanced engine) you still have the problem of the compression stroke in the non-active cylinder that would be sapping power; same again with the vacuum created in the combustion stroke (since there are no expansion of gases).

[heartdisease]

Good read



http://www.greencar.com/articles/var...better-mpg.php

[nogard]

That was a good read, seems like the V6 is the more complicated engine design to do this to. I'm surprised some of those engines don't get better gas mileage with a system like that. How bad would they get with out it?

As far as robbing power, when I've done work to the engine and had to turn it by hand it seems like it is a little hard to turn on the compression stroke, but then after TDC of that stroke the crank "jumps" ahead a little on its own.

I was also talking about shutting off two cylinders, I though this would keep the engine more balanced than running on three.

I was thinking of pulling two plug wires and see how choppy it ran, just to see this first, before I would take it any further. But you are right I'm sure it would be more work that it is worth.

[heartdisease]

Modern engines are amazing. I had a 1981 Monte Carlo. It had a six cylinder to start and if you took it real easy you could squeeze out 21 mpg highway. My Camry has a smaller engine just 4 cyl and moves a heavier car and it will get 35 mpg all day long. Not to mention it has half again the horse power!

I am waiting for Bill Gates latest investment to start paying off. He put some money into this----

http://www.ecomotors.com/

Thay can do variable displacement with this design although I am not sure quite how.


I am also wondering what happened to Cowers engine he was working on-----

http://green.autoblog.com/2007/05/24...-the-steam-en/

and

http://www.popsci.com/scitech/articl...strokes-genius

[white90dx]

Spend your mental energy on something that will give you more results... The 3s-fe has batch injection, and the ECU won't be able to figure out what's happening if you just pump air through a couple cylinders. The O2 sensor will read lean and the ECU will dump fuel to compensate... among hundreds of other problems with the idea.

-Charlie

[270+Camry]

i know you are on the never ending quest for getting the most miles for the least gallons. I've heard that in the 60s cadillac tried to make a "flex" car with servos and pumps and all kinds of crazy stuff. they sort of succeeded but it was a damn scary ride once the other 4 cylinders would kick on and grandma was driving. They tried again in the 80s. All this technology isn't new at all, I guess manufacturers just hadn't found a safe and reliable way to make it happen until the last 10 years. That's one way around it.

I'm half brazilian and back home, half the cars you saw on the road were powered by sugar cane aka ethanol. Here I've also met up with guys running propane cars. There are several countries whose public transportation system is powered by propane, I'm talking taxis, busses. Ever though about switching fuels? I know here in the states the whole sugar cane car probably isn't the best idea cause as far as I know we don't live in a sugar cane producing country. Propane is a lot safer than people would think and you can still run your car on gasoline if you cant seem to find a place to fill up on propane. I don't know, I guess check it out, the conversion ain't even expensive pluss it extends the vehicle life since it is all so much cleaner.


http://www.altfuelprices.com/ has listing of LPG (propane) E85 and other alternative fuel stations near your area along with the prices. it's cool stuff. apparently e85 was more abundant than I thought.