Serious engine question for serious thinkers.

[afterburn 549]

serious thinkers, please

[Jay Auskin]

A couple of issues, one being what happens to the structure of the head. You need enough clamping load to seal the head properly and removing material and putting the ports in there would require the head to probably get bigger in other areas which leads to the second issue.

Packaging. Having designed engine components for 8 years (a while back), the biggest problem was where to put things. Especially on "modern" (last 20 years), hood lines keep getting shorter, and the engine gets shoved further into the firewall/cabin. Re-routing things and putting fuel/coolant/oil/wiring closer to really hot parts requires more insulation/shielding. Then your available packaging space gets even worse.

So, likely the benefit is outweighed by negatives.

Looking at an LT2 V8...it's pretty smooth as is:

[john70t]

I've suspect air movement is a factor as well.
A curve creates swirl which energizes and helps mix the charge in the cylinder.
This goes into serious engineering, well above my pay grade, but the air in the intake is constantly start-stop pulsing and there are a lot of dynamics in effect.

Porting intakes straight and completely smooth will improve consistent high-rpm performance on the track but turn idle and low rpm into slop. Same with big carbs.
Keeping the intake rough creates mixing turbulence but it also creates quench.

Under certain conditions the right combo will keep the higher pressures behind the intake valve and less lag for the next charge.
Daily drivers have to operate in a variety of conditions: Hot/cold, mpg efficiency, idle/cruise/WOT, etc.
There is no golden ticket and there is a trade off for every design.

[speeder]

Nice cut-away, what is the second, (top), chain driving?

[island911]

Originally Posted by john70t

I've suspect air movement is a factor as well.
A curve creates swirl which energizes and helps mix the charge in the cylinder.
This goes into serious engineering, well above my pay grade, but the air in the intake is constantly start-stop pulsing and there are a lot of dynamics in effect.....

^THIS^

I've posted about this before, that as soon as you think of "air-pump" you completely toss out the concerns for thorough mixing of the air-fuel charge.

Complete combustion is the driving factor, especially now days.

[beepbeep]

Hi,

you just described Triflux head. Great for top end power and used in Lancia S4. They did not really care about low range though. As efficiency is the name of the game for mass production, such complex/expensive designs were never deployed.



http://www.speedhunters.com/2013/02/the-triflux/#

P.S. LS2 is not really the "model" engine when it comes to good head flow. It is low profile, cheap to make and reasonably light. But from efficiency point of view, it is old news

[john70t]

I wonder how many ricers get burnt valves when they stick 4" exhaust manifolds on a 1.5L?
(which reduces exhaust velocity, vacuum, and thus scavenging of heat and un-burned particulates)

It's like Twiggy going to the gym and pumping her right leg up like Serena Williams. They'd have to make fashion model runways in a circle.
A complete system is only as strong as it's weakest link.

[Jay Auskin]

Originally Posted by speeder

Nice cut-away, what is the second, (top), chain driving?

I believe it's the lifter valley oil scavenge pump. It's a dry sump motor, and not letting it drain through the engine helps to reduce oil temps.

[speeder]

Originally Posted by island911

^THIS^

I've posted about this before, that as soon as you think of "air-pump" you completely toss out the concerns for thorough mixing of the air-fuel charge.

Complete combustion is the driving factor, especially now days.

This is interesting stuff that I understand a little but not a lot. I'm going to be building the motor for my old Triumph Bonneville soon and I'll be checking in here for advice wrt to porting. I know that it's not as simple as making things smooth and valve size in relation to displacement and CR is crucial with cam lift and duration entering in, etc.

Luckily, there are guys who have been building these engines since Jesus was in short pants but getting any kind of consensus from them on those forums makes this place look like a kumbaya session of Buddhist Monks.

[Rob Channell]

Just ran across this video of some of the design of the Koenigsegg Freevalve design. They can eliminate throttlebodies because the valves can actually perform that function. I was busy thinking how awesome it must be due to the short path and was not even considering swirl or air fuel mix..... It's always the details.

[hcoles]

I'm impressed with this Koenigsegg stuff.

[fanaudical]

Valves? Who needs valves?

https://www.liquidpiston.com/how-it-works

[island911]

Originally Posted by fanaudical

Valves? Who needs valves?

https://www.liquidpiston.com/how-it-works

Nifty, but I will be surprised/impressed if it has reasonable fuel efficiency. - that combustion chamber screams of power-stroke inefficiencies.

[rusnak]

Intake air is not being blown through a pipe. It is sucked via pulsed volume displacement. So you have to think about air velocity, pressure, and turbulence affecting all of the above.

And one solution does not cover all RPM speeds. At some RPM levels, the intake charge can be greater than the volume of the air being displaced (positive pressure) due to the plenum chamber becoming something like a collector. Look at the intake plenum on a Motronic Porsche from the mid-80s. They needed a bit of turbulence to mix the air and fuel together.

When you have DFI, you only look at air velocity and pressure, not so much turbulence/ mixing.

[beepbeep]

Originally Posted by Rob Channell

Just ran across this video of some of the design of the Koenigsegg Freevalve design. They can eliminate throttlebodies because the valves can actually perform that function. I was busy thinking how awesome it must be due to the short path and was not even considering swirl or air fuel mix..... It's always the details.

Basically any gas BMW for past 10 years uses valve lift instead of throttle.
https://en.wikipedia.org/wiki/Valvetronic

Koeningsegg system is not so much about using variable lift for throttling (which is nice side effect), as it is about being able to seamlessly alter valve timing.

[beepbeep]

Originally Posted by fanaudical

Valves? Who needs valves?

https://www.liquidpiston.com/how-it-works

Basically a modification of Wankel engine. Unfortunately, it suffers same issues as any Wankel engine: high surface to volume ratio (= low efficiency) and need for apex seals.


ICE is done. Future is electric. Motors are 99% efficient, compact and powerful. Energy storage on the other hand, there is work to be done. Fuel cells, batteries, inertia wheels...that's where stuff is happening.

[techman1]

Lately I have heard the ICE is done statement reaching a crescendo.

While there may eventually be a replacement, I do not see it as the current proposals of EV.
Or at least I do not think it should be the current proposal. We might have it pushed down our throats.

If I am wrong, please point me in the correct direction of information why. And after proof-reading, I might need more coffee, so please forgive the rambling below.

The manufacturers of automobiles, while they use a lot of resources to manufacture, do not incur a large carbon footprint during the process. Car manufacturers are utilizing vendors who are using more amounts of recycled steel and other materials. And making them even more efficient.

At the end of life for the current ICE cars, there is a path to recycle and re-use. Great that creating more EV's will cut oil/gas production and exploration, but the "fuel" will still need to come from somewhere. Mining of materials for the batteries, and the electricity production for charging.

So by producing more EV's, we are shifting the production of the "Fuel" from after the vehicle is produced, to when the vehicle is produced. (Excluding battery charging)

I have heard there is a problem with the disposal of the hazardous materials in EV's and the recycle path has not been fully developed.

To open your eyes to the problem, look at the current acres of vehicles waiting for recycling, either by crusher and melt down, or pulling the parts. Now imagine each one having a 2-400 pounds of batteries! What the future - 20 years ahead, we might face.

[john70t]

At the end of the day the ICE is still only about 20-25% efficient, despite the tall stack of bandaids thrown on top of it.
Most of the combustion heat simply goes out the tailpipe, or is absorbed by the block which itself has to be cooled by a separate system adding weight and complexity. Then there are dozens of bearings and pivot points to be lubricated which only adds to the complexity.


A plate-style instead of drum electric motor would be the most efficient transfer of energy at this time I would think.
-If it could be reduced to two or even one bearing the friction is almost eliminated.
-Gyro would be a new problem to be solved.
-Just like using a 'cheater bar arm' a plate would create more torque further from the center.
-Plates could be modular and stack-able. Add a bigger cover and slip on a few more. Total parts required between models could be reduced by the mfr.

[rusnak]

Originally Posted by beepbeep

Energy storage on the other hand, there is work to be done. Fuel cells, batteries, inertia wheels...that's where stuff is happening.

Energy store has always been the big problem with EVs from the earliest days. Nothing really new there from a single vehicle perspective. But if you multiply that and impute a number representing the entire current fleet of cars on the road, then the problems become energy production and distribution. And that is when it looks like EVs as currently proposed look to be implausible. That is not even taking into account the cost of ownership and disposing of the materials at end of service life.

[island911]

Originally Posted by john70t

At the end of the day the ICE is still only about 20-25% efficient, ....

That was the case. Not anymore. Mercedes has a 50% car you can buy.

I agree with most of what beep posted BUT the ICE is not going away. The energy density of fuel so vastly outpaces that of the best battery... ICE are not going away. Ata minimum for the production of electricity. Just look at the current FUBAR in Germany and Texas. All of their "Green" wind and solar farms rendered USELESS by snow. Fire up the ICE.