excellent points here. How could i forget about them with both volumes of Taylors books on the coffee table 5 ft from laptop!


Just out curriousity, do the dead cylinders have a problem with drawing in exhuast charges?



Another point Id like to bring up is simply the continual improvement of the Internal combustion engine.

For example, our race engine at work has great BSFC compared to a street car (pump gas). with fuel pressure set at 40psi, we run much smaller injectors than what something like a blown 383 LT1 would need even at 46psi.

I was actually in shock when I saw the numbers all worked out. I was expecting 75-80lb injectors and we ended up with 65ish i think. mmm engineering

 

Here's a quote from Chris Meagher of GM:



"In order to eliminate the pumping losses," says Meagher, "you need to disable both the intake and exhaust valve." This results in a completely sealed, deactivated cylinder, which is essentially an air spring being acted upon by a piston. Virtually all the work put into it during compression is returned to the crank during decompression, finally giving credence to the old joke about piston-return springs. (That's nothing. Wait 'til you hear about the muffler valve...)

"Currently, we could disable just the fuel delivery," says Meagher, "but the valves would still be opening and closing and each cylinder would still be doing work pumping air in and out. So there would be no net gain in efficiency--you wouldn't have eliminated the pumping losses at all."

In support of cylinder deactivation is some very interesting choreography from things ranging from throttle valve modulation to active exhaust tuning, but it all starts with the additional job tasked to the lifters. "We disable the valves through a device called a switching lifter," explains Meagher. "This differs from a normal lifter in that there is an inner body and an outer body connected by a spring-loaded pin. For V-8 operation, the pin is fully expanded by the spring so the two pieces act as one and the lifter acts like a regular lifter. When we want to disable the valve operation, we deliver high-pressure oil to a groove in the lifter that leads to the outside end of the pin, forcing the pin to collapse the spring. Now the two parts of the lifter are free to move relative to one another and as the cam lobe pushes on the follower the inner portion of the lifter pushes against another spring at the top of the lifter and does not transfer force to the pushrod."

 

The new Hemi has "special" lifters like the old man stated above. One of the reasons I think that we don't see performance cams for that motor yet. Another being that DC needs a performance platform for the Hemi. It's probably as good of a motor as the LS motor but it's in pigs for vehicles. I mean why would I give up a performance car for a 4000lbs+ old mans car or station wagon?

On the point of fuel ecomony......

Chamber design has a big part in that, and companies getting much more power thru airflow development. In the 60's the camshafts where a much bigger reason for the HP levels they had. A LT1 in a 1970 Camaro or Vette had a bigger cam to go with the Double Hump heads to make a 360 HP STD not installed in the car, where a LS1 makes the same amount installed in the car in SAE conditions. The heads are obviously better in the ports and chambers, but the camshafts also have much less overlap and therefore have better gas mileage. I think some things that are coming out of the race arena like wet flow development will also play a part in the fuel economy picture. As time goes on it's all the little things added together that make the improvements. Kind of like how the little things in a motor add up to a big gain in HP. 5-10hp here and there can add up to a lot.

Bret

 

haven't they been trying to make additives that make less heat when burned(to transfer it into work, or pressure)?

 

I'm not sure what you mean. Please elaborate.

Thanks.

 

thats what my chem teacher said. i don't think he's a car guy but it made sense when he said it. change in internal energy of a system= heat + work
it was along the lines of if you create heat you give off energy and if the system does work it gives off energy. i guess he was saying someone was trying to change the structure of the gas to create more work and less heat?

 

I'm still confused. We are talking about combustion, right? Isn't the idea to get MORE heat out of each pound of fuel to produce more power to improve the efficiency? Maybe he meant less heat out the tailpipe and cooling system so that more was used to produce power. I'm not sure how one goes about "changing the structure" of the gasoline to do that. The thermal efficiency of internal combustion engines isn't very high, and engineers have been working over a century to improve it.

In any event, I wouldn't look for a breakthrough in this area.

 

My thermo professor was part of GM's plan to make the 60% efficent engine- or at least eliminate lossed through coolant with a ceramic motor.

well the did just that, and now the EGT just doubled

it gained a bit of efficiency, but not much. He (as well as myself) dont believe there is much of anywhere to go with the traditional (think SBC, not hybrid, DOD or antying like that) internal combustion engine. They are pretty much going to be at efficency levels they are at.

Overall, the ICE hasn't done much since 1970ish. BSFC improved a bit, but 95% of it is still the same- most advancements are thanks to improved metalicurgy and machining. EFI is a bit of a jump but overall on the street, its basically just more green happy and reliable

 

I think number77 is talking about some thing like a high explosive fuel insted of a combusting fuel.
Some thing like methanol, nitromethane (CH3NO) or hydroziene. They make more power than gas but you have to burn a lot more of them.

 

Not sure if you guys have seen it yet, but ford came up with an interesting concept a couple years ago. It's mainy geared for city driving. They called it "hydradrive" or something like that and was showcased in the superduty line of trucks.

What it does is utilize hydraulic pressure built up in a tank mounted near the center of the truck. When coming to a stop, a pump mounted on the drivetrain (leading end of the DS) is engaged and uses the momentum of the truck to turn it and build pressure in the tank. When accelerating from a stop the pump is reversed and the pressure built up in the tank is released and the pump essentially accelerates the truck for the first 5-10 seconds. Testing showed that it only took about 30-40% of the energy required to go from a stop versus accerlating under the engine's power only. It's also intended to make it easier for the truck to tow a load since much more fuel is needed to accelerate than cruise with a load. Pretty interesting, would like to see this technology developed and perfected.

Another way to increase mpg could be to follow VW's lead. The jetta TDI can get over 40mpg (i've heard of 50mpg before) on the highway and some 30mpg in the city.

Kinda going on this idea....one thing i've been thinking about is something like the railroad industry uses. They have big 10 or 12 cylinder, 4000+ hp turbocharged diesel engines that only turn generators (these diesels redline at a measly 900rpm and operate normally at 700rpm).... which power electric motors mounted on the truck wheels which moves the train. If motors like these were to be employed in cars and batteries were used, a small diesel engine could be used to only turn a generator to charge the batteries when needed. Say, you're driving down the road and your batteries are at 100% charge, the diesel engine is off, and the motors are the only thing powering the car. You drive for an arbitrary amount of time until the batteries run down to about 30-40%, at which point the diesel engine cranks up (seemlessly and unnoticeably, hopefully) and recharges the batteries until they reach full charge. Then the cycle starts over as needed. This could be used well in city driving too. I guess packaging issues are what's holding the automakers back on a system like this. A single electric motor could be mounted to a normal automatic transmission and get the same benefits fuel-powered engines get with gear multiplication, lower revolutions, etc. Highly efficient batteries and small generators would need to be developed so the engine won't have to run all the time. I'm sure the electric motors could produce a substancial amount of power too.... i live near a railroad track and they will constantly come by, two or three locomotives hooked together, pulling over 150 fully loaded cars at 40+ mph. Who knows how much weight that is? And given that amount of weight, they accelerate at a reasonably fast pace.

Just some random thoughts.....

 

Ford didn't come up with that. Its just an application of the age old concept of a gyroscope/flywheel and inertia.

 

What about turbines driving generators, so that the turbine can be relatively small and stay in an efficient range?

 

More random thoughts..

Yep, the diesel/electric railroad locomotives were probably the first true hybrids! BTW, You have pretty much described current hybrid cars except most are using gas not diesel.

"Reasonably fast pace" acceleration? How about 0-50 mph acceleration measured in 10s of minutes rather than seconds. Hybrid cars actually accelerate well with both IC engine and electric motor helping out.

FWIW, steel wheels on steel rails on a track with a maximum grade of a couple percent is what makes railroads work. Friction is very low except on curves, and once you get them going, it only takes 12-16,000 hp to keep them going. 150 loaded freight cars as somewhere around 30 million pounds. That's in the neighborhood of 18-1900 lb/hp. Any wonder why they are a little slow in the quarter mile?

"Highly efficient batteries" still don't come cheap. More's the pity.

 

finding a way to harness the energy using in braking would be an excellent start too, but without hybrids.


as Oldstroker said, i dont think there is a magic bullet. but 5 or 6 of these 3-4%'s will make a big difference. call me cynlical but i dont think the IC engine will be much more efficient than it actually is right now. just gotta find a way to need less power (gears, weight, aero, hybrid)

I wonder how much electric brakes will help our cause. they should be able to make it so the pad has zero contact with the rotor. I remember my LT1 Z28 around 3 or 4 years ago, with it jacked in the air and spinning the wheel you could hear/feel the rotor rubbing the pads a bit

 

LOL, that's why i used the term loosely. I see those around here coming to a stop, waiting for another train to go over a bridge a couple miles up the track, and then getting back up to 45-50mph (limits set on the tracks around here) in just a few minutes. Quite impressive to me. The latest GE AC6000 locomotives are using 16 cylinder diesels making 6000hp and some 35,000 lb-ft of torque. A couple of those should get 30M pounds moving good.

It still puzzles me that the latest hybrids are one-off, albeit ugly, vehicles. Why won't some of this technology be incorporated in to the vehicles we know to day? The cars, SUVs, and trucks we know today should have enough room available to mount these systems. A normal looking cavalier, accord, ranger, canyon, trailblazer, explorer, durango...(whatever you can imagine) would be great vehicles to use these system in. Most are used only for getting from point A to point B without much need for power. Comfort, looks, and miles-per-gallon are what matter. And emissions too if you're into environmental preservation. The heavy duty line of trucks like the silverado, super duty, and ram will still need their gas/diesel powerplants for obvious reasons. And also the performance cars like the vette, viper, mustang, hopefully future f-body will have their need for it too. But much of everything else out there is just wasting fuel. I spend around $30/week on gas in the camaro, ~$1,500/year on fuel. Cutting that expense down to a 1/4 would justify spending a few grand more on a hybrid vehicle i actually like in the long run. Oh the benefits of a capitalist, petroleum driven economy....

I'm sure the cost is the main thing... but with prices rising on everything else wouldn't this balance out? I mean if more vehicles on the road today were to adopt these systems wouldn't the need for petroleum drop and the prices with them too? Less money spent on fuel means more money in people's pockets, and that can be used to afford slightly more expensive hybrids and then save money in the long run. But it all is just a dream for now....

Detroit does have somewhere to go from here. I hope they just get there really quick. I'm sick of paying $1.90/gallon for gas. And paying rising tuition too.... it's more than doubled here at CU in the last 2 years. $4300/semester sucks.... it was $2000/semester when i transfered here back in 2002. And my sister in med school is paying $40k/year. It's rediculous.

Whoa... got a little carried away there. If only i had more money haha