Improving Engine Efficiency & Performance

[torq455]

i remember my dad putting leaded gas in his GTO. pretty sure we still had that in the early 80's still.

just confirmed it was phased out by 1986.

[pocket-rocket]

True about the muscle cars and high compression. Though they did have 100 octane rating which would allow a poorly low tech IRON head engine run safely.

I don't remember my dad putting leaded gas in his truck, so that was before my time. Man I grew up in the wrong time era

[torq455]

Maybe I can't do it by hand, but the electric starter motor doesn't have any trouble doing it, and it's only a couple horsepower, maybe 5 at the most.

Maybe, though don't forget about the little gear that turns a much, much larger gear.

[torq455]

Actually in the mid 70s when the emissions situation hit, compression ratios took a nosedive. Back in the muscle car era it was nothing to have a compression ratio in the double digits up until the switch to unleaded gas. I read about a Camaro that came with 12.0:1 compression stock. Cars today stock haven't hit that mark either. Not the 08 Z06, Viper, or the Enzo.

True about the muscle cars and high compression. Though they did have 100 octane rating which would allow a poorly low tech IRON head engine run safely.

[pocket-rocket]

Well one part that made sense to me was that our compression ratios of today aren't what they could be. One of the weak links to engines is the cylinder head according to that guy. Remove it and put 2 pistons going at each other and you get a much greater compression ratio. I checked the compression on a 97 Tahoe w/ a 350 Vortec. The pressures were all right around 200psi. IIRC, that guy said the pressure at TDC in that engine approached 4k. That sounds like a really high compression ratio to me. Turbos normally run what, around 15 psi if you know what you are doing? I don't know all the math on it, but I doubt after the piston hits TDC in an engine running 15psi of boost it is going to be anywhere around 4k psi. I don't see that tiny engine making 900 hp though. Even with 4 cranks to absorb the hp, I don't see them taking 225 hp each because they all looked like they were about 1" diameter. If I watched you try to shove 225 hp to a 1" crank to catch... Lets just say I won't be staying in the room with you :P

[Bones]

You are using 1 combustion event to power 2 pistons.

This is the part that lead me to call it a gimmic. The best way I can come up with to explain it is if you stuck a plate in the middle of the cylinder and divided the incoming charge between both halves the engine would not perform any differently than if the two cylinders were side-by-side. The plate would always have the same presure on both sides and it would be like it was never there.

[SappySE107]

Its not going to be the total answer, but that would simply their design when its actually doing more than just reducing friction. You are using 1 combustion event to power 2 pistons. The power is divided to 2 cranks per piston but the cranks are all connected together, which brings the power to 1 output shaft. You can have a lot more stroke without any rod angularity and side wall friction. With the reduced size of the components and the power potential, your RPM could be much greater as well.

I am not the greatest at explaining things but the design made sense to me.

[Bones]

pumping losses are 10hp at 7k and frictional is 56hp.

OK, you got me there. When volumetric efficieny is high, pumping losses are going to be low.

I'm not saying reducing friction isn't important, just that engine efficiency isn't going to suddenly jump 50% by reducing friction.

[SappySE107]

So the cylinder head doesn't absorb any heat energy? Right. And 2 pistons moving at each other is a gimmick? Only because you don't understand or have any desire to open your mind to concepts you haven't heard before.

pumping losses are 10hp at 7k and frictional is 56hp. Thats through simulation software, which is based on a lot of real world testing and math. Please provide some proof of your claim that pumping losses are greater than friction. So far you are only concerning yourself with thermal losses.

[Bones]

I guess he skipped the part on direct injection and the higher compression possible from 2 pistons moving at each other vs 1 piston moving against the cylinder head.

Diesels have always used "direct injection", they have to be to prevent pre-ignition. And the 2 pistons moving away from each other is another gimmick. A cylinder head doesn't absorb any energy, so there's no loss assoiated with using one. The pressure in the cylinder is pushing on two pistons but in order to do a direct comparison the pistons can only move half as far as a single cylinder with the same bore size. If the pistons moved the same distance the engine with 2 pistons would have twice the displacement so it wouldn't be a fair comparison.

edit: next you'll try to convince me that his "electric supercharge" is a valid technology? I'm not trying to be an argumentative dickhead, but all the ideas this guy is trying to sell are bunk. you could probably dig up thousands of old patents for ideas just like these.

[Bones]

you ever turn an engine over by hand without the spark plugs in? try spinning it at 500 rpm manually. too much work and can't do it huh? hmmm....no pressure still built up after combustion since YOU are doing the work. that means there is a lot of friction there. that's why an internal combustion engine is so inefficient. not to mention the fact that is has to overcome compression forces.

Maybe I can't do it by hand, but the electric starter motor doesn't have any trouble doing it, and it's only a couple horsepower, maybe 5 at the most. The source of the inefficiency in an engine is NOT friction. Pumping losses however are. Like you said it's easier to spin an engine with no plugs because you only have to overcome the friction and not the pumping losses. Even so if the average engine is 20% efficient then that means a 200 HP engine is burning 1000 HP worth of gasoline (in terms of the actual chemical energy stored in the fuel) and I can assure you that it doesn't take even close to 800 HP to spin a non-running engine at 6000 rpm.

Internal combustion engines make power by turning chemical energy stored in the fuel into heat energy, which is then turned into mechanical energy. So any heat energy that dissipates into the atmosphere without being turned into mechanical energy is considered waste. That includes heat that goes out the exhaust, heat from the radiator, the block, etc. In thermodynamic terms it's all wasted energy.

I'm not saying that there haven't been improvements or that there won't be more improvements in the future, but those improvements tend to be evolutionary rather than revolutionary. The only exception that I can think of is the Crower 6-stroke engine which is an attempt to reclaim the energy that is normaly wasted through the radiator.

Anyway, we all know what they say about arguing on the internet...

[SappySE107]

I guess he skipped the part on direct injection and the higher compression possible from 2 pistons moving at each other vs 1 piston moving against the cylinder head. Frictional losses increase with RPM, so the more you have to spin the motor to make more hp, the more you lose. The crank spins on a thin layer of oil. Most of your friction comes from the rings and piston in the bore, not the rotating assembly.

At 7k, you lose roughly 56hp on a 3400 due to frictional losses (according to dynomation 5). While there are multiple areas to address to increase efficiency, the friction loss is more significant than you think.

[pocket-rocket]

Actually in the mid 70s when the emissions situation hit, compression ratios took a nosedive. Back in the muscle car era it was nothing to have a compression ratio in the double digits up until the switch to unleaded gas. I read about a Camaro that came with 12.0:1 compression stock. Cars today stock haven't hit that mark either. Not the 08 Z06, Viper, or the Enzo.

[torq455]

you ever turn an engine over by hand without the spark plugs in? try spinning it at 500 rpm manually. too much work and can't do it huh? hmmm....no pressure still built up after combustion since YOU are doing the work. that means there is a lot of friction there. that's why an internal combustion engine is so inefficient. not to mention the fact that is has to overcome compression forces.

wow! "NEVER never going to be a revolutionary improvement in efficiency." soooo since the eairly 1900's, the engine has seen no improvement? variable cams including lift and duration (electronically controlled), variable intakes, EFI, computer designed camshafts, ceramic coatings, anti-friction coatings, more efficient flowing exhaust systems (metal catalytic converters) , direct injection, turbos, lower friction synthetic motor oils in thinner viscosities, and there has even been a running concept of a variable compression engine. with more research and technology involved, compression ratios have been rising making the engine more efficient alone.

initially, i did think SappySE107's comment of sharing uneducated comments was a little harsh. however i'd say that i have to agree with him 150%!! please research first.

[Bones]

Yes, it takes all kinds. Now that you are here, i suggest learning a bit before sharing your uneducated comments.

What was uneducated about my comment? The engine design this guy is talking about doesn't do anything different than a normal diesel engine. The part about having a second connecting rod and crank to reduce side load on the piston is neat but the frictional loss of having the piston pressed against the cylinder is pretty small, probably less than spinning the extra crankshaft. The thing that makes internal combustion engines so inefficient is that there's still a lot of heat and pressure in the cylinder at the bottom of the stroke when the exhaust valve opens and it all blows out the tailpipe. Unless someone finds a way to tap into that lost energy there's never going to be a revolutionary improvement in efficiency.