Been thinking- variable-output engines?

[Slimer]

Ok, so I've been thinking about an automotive concept that seems like a no-brainer with today's technology, and that would go over like gangbusters. It occurred to me as I was putting down the highway into the mountains in my Vibe, wishing I had a few more horsepower to get me up the hill. Here's the idea. All engine power outputs are compromises: there will be some contexts where the output of your engine is inappropriate, and some where you do just fine with what you have. There's no advantage to driving a V12 BMW over a 4-cyl Vibe in the city. There's no hope for a 4-cyl Vibe on an Autobahn. Driving a V12 in a city is wasteful and inefficient, and there's limits to what an engine suited to the city can do if you need to open it up on the highway. So why not get the best of all worlds? You've got a small 4-cylinder turbocharged engine- it could be gas, or a modern, clean, efficient turbodiesel. I'm picturing a BMW Valvetronic engine, which has no throttle because its valve lift is variable, and has variable valve timing on intake and exhaust cams. Basically, every aspect of the engine's operation is controlled by computer. There would be two very small turbos feeding air into the engine, also computer controlled and able to be turned on and off. Say you're driving in city traffic. You don't need a lot of power because it's stop and go, and city driving isn't that efficient. You reach out, twist a knob to "City" and drive off. The turbos are disengaged, the fuel/air mixture is lean for efficiency, and the engine management tunes the valve timing for higher torque for high responsiveness at low speeds. You're putting out maybe 115 hp at this point, but that's ok, you don't need more. You get 30mpg in the city. Say you take a road trip. Switch to Hwy. You're cruising at high speeds. One turbo kicks in, the power jumps to about 170hp, and engine management changes to optimize highway cruising. You've got lots of power to cruise and pass, but you still get great mileage. Or maybe you're on a twisty road and want to have some fun. Switch to "Sport". The engine goes nuts. Both turbos uncork, blowing together, and power goes to about 240. Its power output is tuned now for lots of power, brutal speed, sportiness. The throttle response is sharp, the engine revs like a demon, you laugh your (removed) off. This could be combined with other technologies. If you had an automatic or F1-style transmission, the transmission processors could change shifting behavior to be relaxed and efficient or brutal and fast. Adaptive suspensions (with air springs or the new adaptive shocks on the Corvette) could work with it to give you a squishy, comfy ride in the city, high-speed stability, or unforgiving sportiness. Basically, this would let you have your cake and eat it too; power when you want it, and efficiency when you want it. The car would respond to your driving style, and you would have just what you need at your fingertips instead of compromising in various situations. And, with today's computer-controlled engines, whose every behavior is dictated by computer, how hard could it be to make that computer switch programs on demand? It needn't even be as tech-heavy as I'm describing. A simple base Vibe engine could be switched to put out either 130 or 170hp, for example, just by modifying the engine computer. It surprises me that this hasn't been done; it would be a way-cool, low-cost way to go about things, and consumers would love it.

[satur9]

i dont know that first one sounds expensive and complicated. i think a vibe with a supercharger or a vibe gt(with a little more torque(i wonder how the torque on the 05's is)).if fine for most everday people.some of that stuff you said sounds a little like g.d.i engines there out there but stil pretty complicated and expensive.

[MonotoneSatellite]

Both GM and Chrysler have displacement on demand engines. Under heavy driving, all cylinders are used. While cruising on the highway or at constant speed, the engine shuts off up to half of the cylinders to save gas.For many years the Vette has used 1st to 4th shift in the six speed transmission under normal or relaxed driving. An actual gate closes and pushes your gear selector into fourth gear instead of second. This is done to save gas. The Vette can also come with a magnetic ride control option that gives the driver a modest ability to tune the suspension to a sport handling setting or one more suitable for daily drivingLiquid viscus all wheel drive systems give decent power to all four wheels when needed. If the primary drive wheels grip, the secondary drive wheels receive no power. This give the driver the best fuel milage to traction ratio available.The examples above prove that systems like you proposed are fully attainable. Right now, the cost is the main reason that you aren't able to get all of these systems on a car. The R&D costs to develop and implement them are incredible. But, that being said, I can't wait to be able to buy a vehicle with a setup like you described.Thanks for dreaming with me. Lets hope we see something like this soon.

[Stang2Vibe]

It all sounds pretty cool to me, as long as I can keep my car on the "sport" setting at all times. Driving around downtown Pittsburgh is so frustrating that its necessary to use every bit of power available to keep 18,000 a-holes from cutting you off when the jerk in front of you decides to make a left turn and not signal, blocking you in. Then you have to sit and wait for the light to change 15 times to get through an intersection because everyone gridlocks it. And there's the traffic lights that turn red for no reason: no cars coming from the other direction. If we really want to save time and gas, make it so those lights quit turning red for no reason and I have to sit there like an idiot at a red light that is letting nobody through.Also you mention F1 style transmissions with adaptive shift points. I say screw that. I need a manual transmission. I don't think there's an automatic transmission equipped car that I can currently afford that will roast the tires from a dead stop like a decently powered manual will. I need that tire roasting ability to get other people to back off and/or get the hell out of the way and quit lollygagging around when everyone else has somewhere they have to be. I've found that a nice puff of tire smoke and a lot of tire screaming is highly effective at accomplishing that. Pokey people in front of you will even pull over to get out of my way. I almost feel bad for them because they then have to sit there for about 5 minutes so that the 10 mile long train of cars that they were holding up can get by. I don't want to drive angry, but I have to almost every day to get anything done. My Vibe just recently hit 17,000 miles and will be 2 years old in two more months, and I'm already on my 3rd set of tires. I'll need another pair of snow tires too before this winter. And I've yet to have an automatic transmission hold up to my driving so that auto tranny better come with at least a 5 year 60,000 mile full and unconditional warranty with guaranteed loaner car for it to be of any use to me.

[FusionVGT]

The Chrysler 300C/Dodge Magnum RT have HEMI engines that cut four cylinders at cruising speeds. The engine drops the cylinders in .04 of a second, and after driving them I couldn't tell when they were firing or not.

[Stang2Vibe]

Yes, I almost forgot about those. The Ram trucks have that as an option also but I've heard that they're having a lot of trouble with them. Every time I hear about this type of engine, I can't help but be reminded of the early 80's Cadillac 4-6-8 engine that was a total disaster. Granted, technology has progressed light years since then, but I still can't help but think that if it could be done practically and reliably they would be in almost every car by now. Look at how every Japanese carmaker has avoided this like the plague. They have turned to variable valve timing to make smaller, more fuel efficient engines feel bigger and torquier. They're even still playing with rotary engines, anything to avoid this. There must be something in the physics and mechanics of these variable displacement engines that just doesn't allow it to work well. Unless that obsticle can be overcome, I don't see this setup becoming popular.

[FusionVGT]

The foreign brands can't do it because they use multi-cam engines and there's no clean way to deal with cylinder de-activation. The HEMI uses one cam so it's a lot easier. Similar to lift engagement, their cylinder de-activation is done with hydraulics. I predict GM's new system won't be as realiable because they're retrofiting it to existing engines now. Chrysler's engine is a clean-sheet design.

[noginsk]

Why has nobody talked about electrically assisted engines in this thread? Personally, I think that Hybrids are here to stay and will be mainstream well before these other technologies make it. There are only two downsides I can see to them. Extra weight which will reduce handling ability, and batteries need to be recharged sometime. Can't just run to the "electric station" and fill up your "tank" with electricity. That makes me think of fuel cells....Hell. Combine them all! On demand turbos, cylynder deactivation, and electrical assist! 100 HP when you don't need it and 500 when you do!OK, back to reality...

[Slimer]

With displacement on demand, the improvement in efficiency is not that great because you're dealing with mechanical friction, which is a big part of the wasted energy in a gallon of gas. Displacement on demand is for ****. The way I see it, modifying the engine program continuously to accomodate demand is a far better way to go, at least for smaller engines. The system is far less complex, can be controlled electronically instead of mechanically, and would be more flexible for a wide number of applications than DOD. DOD basically just shuts off one half of the engine when you don't need it. It still doesn't improve efficiency in city driving, or allow you to choose the power output you need. The system is not that complicated or expensive. Turbocharged engines are all over the place. Direct injection engines are all over- Audi/VW makes some very good ones. Twin turbos are not that much more expensive than a single one. You might be talking a small premium, but in exchange for basically getting an entire engine range in one. That'd be a bargain at any price. It could also actively sense what you want in any given situation, which just occurred to me. Dial down the power when cruising, crank it up when passing, for example.

[Slimer]

Stang- I'm talking about a robotic manual like BMW SMG, not an automatic. Essentially a manual with an electromechanical actuator to shift it.

[DocHolliday]

Well, the 1ZZ and 2ZZ at least have the variable valve timing, and the cam phase changeover in the 2ZZ does provide extra power when one has the space to fully wind out the engine.

[satur9]

tQuote, originally posted by Slimer »Stang- I'm talking about a robotic manual like BMW SMG, not an automatic. Essentially a manual with an electromechanical actuator to shift it. the new toyota mr-2 have a electric control manual in them. still not as fast as the stick.mabey someone here who want to shift but doesnt want a clutch pedal can swap one(tranny, the engine is the same)

[futseal04]

Quote, originally posted by FusionVGT »The foreign brands can't do it because they use multi-cam engines and there's no clean way to deal with cylinder de-activation. The HEMI uses one cam so it's a lot easier. Similar to lift engagement, their cylinder de-activation is done with hydraulics. I predict GM's new system won't be as realiable because they're retrofiting it to existing engines now. Chrysler's engine is a clean-sheet design.Actually, it was in the design from the git-go. GM has been there before, if you remember the Cadilliac V8-6-4 disaster of the early 80's. The new LS2 has had that in mind from the beginning, but won't be offered at launch.And Mercedes has cylinder deactivation on some of its V12 engines, which are an OHC design. As for the SMG topic, this is only one of the options out there. Ferrari has the F1 system on the Enzo and Modena, and Audi is coming up with on for use on the R8 I believe. These are true manuals that use computers to match engine speed and drive speed when shifting gears. The type int the MR2 is similar to those used in Jaguars, Chryslers, GM products, etc and are merely an automatic with manual gear selection.While we are on the topic of technical innovation, I might as well use this time to tout my support for hydrogen powered cars. Not fuel cells, but H2 powered Internal combustion engines. The tooling costs are not as significant as one would think, and offer the performance that people desire, whereas fuel cells do not. Imagine.....a H2ICE with a hybrid drivetrain. You can make the ICE any size and have the hybrid to assist around town or whenever accleration is needed.Just a thought.....

[satur9]

the mr-2 is not a autostick.its a tru clutchless sequential manual.july 2002 sport compact car,check out the review