I notice that GM has started to push cars with engines using cylinder deactivation technology:
http://www.sciam.com/article.cfm?chanID=sa001&articleID=000F2BEF-ECD0-119B-ACD083414B7F0000
Is this technology applicable to diesel engines and is it being used?
Deactivating cylinders in a diesel engine makes little sense unless you can actually stop them (I mean, stop the pistons and valves).
Gasoline engines waste some power while aspirating at partial loads (because of the throttle valve); cylinder deactivation reduces these power losses. Diesel engines have no throttle valve so there’s no power to save in there.
…This is a very interesting development of engine design that seems is destined to be very popular and useful for fuel efficiency and will be coming on fast. Up to 20% is a sizeable savings. And still have performance available as needed.
I own a 2005 Dodge Magnum, with the 5.7 liter Hemi…at constant highway speed, it “drops” four cylinders…full throttle, 340 hp off the showroom floor, yet on a drive from Houston to Galveston, it got 32mpg…not too shabby!
Average city, 21mpg, average highway, 27mpg.
Look for this system to “save” the high horsepower V8s…
Ed
I guess I will have to witness one of these new engines first hand…I just can’t shake the notion in my mind of an engine with a spark plug wire or two loose and the engine bucking and shaking due to not firing on all cylinders…If an 8 actually does run like a 6 or a 4 normally would, I still can’t picture those pistons still running up and down without firing and not getting vibration or imbalance as half of the engine is rotating without firing. Dave Williams http://groups.yahoo.com/group/nsaltoonajohnstown
Ed, going through Google citations it looks like your car is on the leading edge. A picture of your 5.7 Dodge Hemi:
http://www.ai-online.com/issues/article_detail.asp?id=462
I also found that it’s also called Displacement on Demand (DoD) technology.
I’m not certain if this is the diesel version of DoD, but a short note in the same article says:
“Eaton Automotive: … developing valve deactivation systems for light- and heavy-duty European diesel engines.”
Eaton supplies hydraulic valves, which permits cylinder deactivation, for GM’s DoD engines.
Apparently Navistar is also working on diesel cylinder deactivation:
http://waw.wardsauto.com/ar/auto_international_says_new/
The switch from 8 to four cylinders is so smooth you never notice…unless you happen to be watching the tachometer.
It drops for a just a second, and the in dash information display on your gas mileage starts to climb.
One thing, you must, and this was stressed a lot by the service manager at the dealer where we purchased the car, you must change the oil every 3000 miles or three months…no cheating that extra 3000 miles like you could before.
That, and regular air filter changes are the key to keeping these engines performing correctly.
The MAP sensor can adjust for a slightly dirty air filter, but dirty oil will leave deposits on the locking pin mentioned in the article.
Couple this engine with a electronicly controled transmission, 32 mpg freeway isn’t un reasonable.
The shift points on the tranny are decided by the on board computer( really a series of fault code programmed chips) so depending on the engine temp, outside air temp, and the throttle position, you can get almost instant aceleration.
Although I haven’t been to the local drag strip yet(my wife would beat me senseless) due to the lack of time and spousal fear, I did have a friend with a stopwatch go for a ride with me.
On street asphalt, 80 degrees outside air temp, from a standing start, we got consistant 4.5 second runs 0 to 60mph.
We could not achive consistant results on 0 to 120…the on board system kept adapting to something, and we would get a few quick runs, followed by a slow one.
And this thing handles great…according to the Chrysler people, its a E class Mercedes chassis knock off, with the independent, or “live” rear end, like a Corvette uses.
Body is about 50% plastic, the hood, roof and rear hatch are pressed steel, the front and rear quarters are plastic, the doors are steel frames with plastic.
A lot lighter than I expected, but rides really nice.
Six foot plus passengers can sit in the rear seats, and still have leg
…Ed, sounds like you have a good one…Chrysler 300C and Magnum are listed as 0 to 60 in 6.2 sec. in article depicting Car of the Year…Motor Trend.
Your description of body parts being a combination of plastic and steel is the first I have read anything about that…Nothing in all the articles I have consumed on those cars.
And by the way, the new Mustang is 300 hp. The V-8, that is…
And…coming is a 425 hp version of the 300C…
DW…on the engine shaking from loose spark plug wires…Point well taken but they have figured out the proper sequence when to fire the reduced number of cylinders and the valves remain closed on the deactivated cylinders. As for out of balance, I’d suppose we have to consider all the mass is still present regardless if that cylinder is firing and the engine remains in balance.
In cylinder deactivation - both the exhaust and intake valves remain closed on the deactivated cylinders. The air trapped inside acts like a spring - absorbing energy on compression and releasing it on expansion. However, compressing air like that heats the cylinder. With that and the lack of cooling from the expansion of incoming fuel, the deactivated cylinders can run hotter than an active cylinder - thus the need for better lubrication and morefrequent oil changes. Those needs may inhibit the use of cylinder deactivation on locomotive prime movers due to the reliability requirements.
dd
Why would the valves need to be closed? The 97 F150 we have was the first truck to have fail save cooling in which if you would lose coolent and overheat, the injectors to four cylinders are shut off and they pump air to cool the engine. Computer controled “distributers” (really now modules) and injectors allows the engine to protect itself or become efficient when extra power isnt needed.
Diesel’s with their radically simpler ignition system would be a easy to shut off cylinders, but more mantainence is reqired. I’m sure if it saved money everybody would do it. I just think electronically reduced horsepower is the way to go. Thats what my diesel performance chip lets me do. But for some reason my chip stays in the +100 hp setting 
Adrianspeeder
…Adrian…I don’t have all the answers of your question on why valves are commanded to remain closed in less H P position…but I believe one reason is to retain heat in the non operating cylinder so when it is reactivated it is heated up and puts out less polution as opposed to being cold and reactivated to use…Probably would upset the air-fuel-exhaust mixture passing through the catalyst muffler and cause additional problems to clean up…
With gasoline engines - both valves must be closed or the engine would pump the raw fuel/air mixture from the intake to the exhaust. That could turn your catelytic converter into a flame thrower and start the EPA breathing down your neck.
Diesels don’t have that limitation - but you want to keep the cylinder hot so that it is instantly available when the power need increases. Cold cylinders don’t burn diesel well - so again the pollution cops would be after you.
dd
Ok, you got to keep the valves closed.
There would be no raw fuel in a fuel-injected gasser because the injectors are simply shut off by the computer. Along with the non-distributor sparkplug control a modern gas engine; there is actually a lot of individual control of cylinders.
There is an easy way to shut of the individual injectors for diagnostic purposes on my powerstoke. Of course I would never drive like that as then I wouldn’t be able to put all them ricers in their place.[:p][:p][:p]
Adrianspeeder
…Yes, I believe each individual injector would be controlled by the computer {easily done now}, and no raw gas would be headed for the {dead}, cyl. even if the valve was open on the intake stroke…but as I mentioned above, I believe they want the valves closed for given reasons…
As for “ricers”…as in Japan…{funny}, my auto is one and it takes me in {complete}, comfort and quiet…and excellent fuel economy. Also with good performance. But then, I believe Adrian is after those trucks…Ha.
I wondered about balance without all cylinders functioning, but I guess the problem is solved. Sounds like that Chrysler is a fun car to drive.
It is, makes for a nice little “sleeper”…as long as they dont notice the HEMI badge on the side…
Ed
Actually on a Diesel engine it is not as hard as you think to deactivate a clyinder as you think. Caterpiller and navistar have been using a Hydraulic unit injector for years on some of the mid range engines. I had a chance to drive a truck eqipped with one of those engines company I drove for was tring to see how they would due in local service. the one I was driving had a clyinder cut out system on it to lower fuel cost in heavy traffic when you were creeping along in heavy traffic it was running on 3 instead of 6 clyinders to save on fuel. The only way you could tell when it was kicked in was you saw your tach drop. On those engines the valves opened and closed like they would of normally and I at least did not have any problems with excess smole when I needed the other 3 to kick in.
I had that happen to the Acura I used to have. Catalytic converter trapped all the fuel, and burned inside. Car bogged down and died, wouldn’t restart…a cop pulled up and asked if a realized the car was smoking…the catalytic converter was glowing red burning the grass under the car. At the shop, the they pulled the CC and it was clean, an empty tube, with the element and baffles completely burned out.
…I was tempted to have them put it back on as it was…[}:)]
Wouldn’t the solution be to have the ignition computer monitor the cylinder temperatures and activate the cylinder when it drops to a minimum threshold and then cut out an active one? Of course you’d have to have sensors for each cylinder.
The stories in both of the links I cited above mention that both Navistar and Eaton are working on controlling valves. Would the valves be held open or shut on a deactivated cylinder?
…From what we seem to know so far, I’d say they would stay shut…