Engine technology thread.

[Dimman]

Originally Posted by Ryephile

Yup I think you've nailed it there. The FT-86 was never supposed to offer performance-metric bragging rights for anyone. It seems that Jack Hollis' speech during the FR-S Concept unveil was more revealing than most of us assumed or hoped; the car is about a balanced approach, not being a one-hit wonder, be it HP/L, BMEP, or outright power. It's not about any of that, it's about reasonable power, reasonable torque, reasonable fuel economy, reasonably light, reasonably affordable. That last bit is still TBD though.

Nice thing is that the torque has likely been 'socialized' and re-distributed to lots of poorer rev numbers. That means with some 'capitalization' and giving most of it all to an elite set of rev numbers, we can bump it up. Maybe significantly. This would of course work even nicer with a set of cams that move the optimum intake air speed a couple thousand rpm up...

(My book shipped last week, so once I get it I will be throwing around some fantasy header/intake tuning ideas to help me achieve this.)

[Silverpike]

Originally Posted by Ryephile

It's not about any of that, it's about reasonable power, reasonable torque, reasonable fuel economy, reasonably light, reasonably affordable. That last bit is still TBD though.

Indeed, you can only have so much of each one at a time.

[serialk11r]

yoo hoo you guys ignored my post on variable valve lift :P

[Dimman]

Originally Posted by serialk11r

I think I just figured out the mystery behind the slow introduction of continously variable lift/duration...

http://www.sciencedirect.com/science...10218075900644
"While combustion stability at very lean operation is guaranteed, intake air throttling in the part load range is necessary to keep combustion temperature high enough for effective oxidation of CO and HC."

Doh. Stupid emissions s***. Do European cars really stink that much more then?
From this perspective D-4S makes even more sense; At low load they can keep temperatures higher if they use port injectors. This is also probably (IIRC) why BMW uses massive amounts of EGR at part load.

They measure differently and have different priorities. How? No idea. CO2/driving distance seems to be a big deal there.

(there's your variable lift response, )

[serialk11r]

Ironic that over in the US we seem a bit more desperate for fuel yet we have low taxes on fuel, everyone drives a honking 6 foot tall 2.5 ton SUV, no displacement or fuel economy tax exists (for large vehicles at least), and our emissions regulations are so strict that fuel economy takes a pretty big penalty.

I really hope that by the time I have cash to get a car, they will have this emissions crap sorted out. Then I will be able to tinker with my crankshaft-driven-turbo-compound-charger idea Since that will likely be past 2015 I have my fingers crossed.

[arghx7]

Originally Posted by serialk11r

yoo hoo you guys ignored my post on variable valve lift :P

You took a lot of stuff out of context. That is an abstract of a paper on very early stratified charge gasoline direct injection prototypes from the 1970s. That paper's particular prototype has a prechamber, a design which has long since been abandoned.

If you look at almost all the current mass produced GDI engines, they are maintaining catalyst temperature by running "split stroke" during warm up. There is an injection during the intake stroke and an injection late in the combustion stroke, with very retarded spark timing.

During warmup the D-4S system has carefully tuned injection patterns that divide up injector duty between the port and the direct injectors. On the 2GR-FSE engine (IS350) during warmup 65% of the fuel is delivered by the direct injectors:



Direct injection + variable valve lift works just fine for emissions when you optimize everything. BMW is doing it on their N55 engines (335) and Nissan is doing it on their VK56VD (M56) engines.

[serialk11r]

Oh okay. Thanks a lot for the info

Then to the people who seem to have more expertise in this, what is the reason that both Toyota and Nissan have not been nearly as aggressive as BMW in implementing these systems across their lineups? Nissan uses it in VK56VD and VQ37VHR, Toyota uses it in Europe and Japan xZR-FAE engines (which aren't found in all cars running ZR engines I think), and that's it. Is it because Toyota already is more or less passing fuel efficiency standards and wants to cut cost?

[Dimman]

Originally Posted by serialk11r

Oh okay. Thanks a lot for the info

Then to the people who seem to have more expertise in this, what is the reason that both Toyota and Nissan have not been nearly as aggressive as BMW in implementing these systems across their lineups? Nissan uses it in VK56VD and VQ37VHR, Toyota uses it in Europe and Japan xZR-FAE engines (which aren't found in all cars running ZR engines I think), and that's it. Is it because Toyota already is more or less passing fuel efficiency standards and wants to cut cost?

Probably a lot to do with it. Toyota's never seemed to jump on to the lift (staged or variable) bandwagon. They didn't use it on the LFA. Yet they continue to refine the VVT-i (now with electronic motors instead of oil pressure). Philosophy maybe?

[Dimman]

Well I finally received my copy of 'Scientific Design of Exhaust and Intake Systems'.

I now know why Burns has no problem revealing their 'secrets' to the world. This book is HARD to read. First off the technical issue itself with the pressure/sound waves is tough. But it is also written in "Olde Imperial Technical English". I pity the metric-trained people reading it. I have enough trouble with it and I speak "Middle Imperial Blue-Collar English". They have a unit called a 'dyne'... And 'psi' is written lbs/in^2. Argh...

Going to be a slow read.

[cossey]

Originally Posted by Dimman

Well I finally received my copy of 'Scientific Design of Exhaust and Intake Systems'.

I now know why Burns has no problem revealing their 'secrets' to the world. This book is HARD to read. First off the technical issue itself with the pressure/sound waves is tough. But it is also written in "Olde Imperial Technical English". I pity the metric-trained people reading it. I have enough trouble with it and I speak "Middle Imperial Blue-Collar English". They have a unit called a 'dyne'... And 'psi' is written lbs/in^2. Argh...

Going to be a slow read.

a dyne is force from the old CGS system isn't it? so atleast it is metric just not SI.

I would suggest "Design and simulation of four stroke engines" by Gordon P. Blair if you don't already have it as technically strong but clear textbook (in SI too)

[serialk11r]

Originally Posted by Dimman

Well I finally received my copy of 'Scientific Design of Exhaust and Intake Systems'.

I now know why Burns has no problem revealing their 'secrets' to the world. This book is HARD to read. First off the technical issue itself with the pressure/sound waves is tough. But it is also written in "Olde Imperial Technical English". I pity the metric-trained people reading it. I have enough trouble with it and I speak "Middle Imperial Blue-Collar English". They have a unit called a 'dyne'... And 'psi' is written lbs/in^2. Argh...

Going to be a slow read.

lol, of course psi=lbs/in^2, that's the correct way to do it :P

Why are the units a problem? Units don't have anything to do with the actual physics.

[Dimman]

Originally Posted by cossey

a dyne is force from the old CGS system isn't it? so atleast it is metric just not SI.

I would suggest "Design and simulation of four stroke engines" by Gordon P. Blair if you don't already have it as technically strong but clear textbook (in SI too)

I don't think it's metric because everything else is imperial. Not really my area of expertise at all...

Originally Posted by serialk11r

lol, of course psi=lbs/in^2, that's the correct way to do it :P

Why are the units a problem? Units don't have anything to do with the actual physics.

It's the language of the text. Some things are just difficult for me because of my lack of physics. Stuff like condensation and rarefaction for waves. This stuff is just new.

The unit is also a language thing for me. I'm used to psi, rpm not lbs/in^2 and rev/min. This just slows me down (albeit briefly) when I read because I have to pause to 'translate'. It's just not a 'smooth' read for me.

And the rest is just full of automotive 'British-isms'. Again a need to 'translate'. I prefer intake to inlet valve for example, muffler to silencer, hood to bonnet, fenders to wings, etc... They even spell carburetor differently.

Finally a lot of examples are old and also British. They had a 4 cylinder motor that had 3 exhaust ports, the center one being 'siamesed' so shared by the two middle cylinders. Weird.

Going to be slow going for me.

[old greg]

Originally Posted by serialk11r

Why are the units a problem? Units don't have anything to do with the actual physics.

Except in the case of Slugs. I f'ing hate Slugs.

[cossey]

Originally Posted by old greg

Except in the case of Slugs. I f'ing hate Slugs.

so you wont be saying that wour shiny new FR-S weighs 83 slugs when asked?