For my English class we have to do a research papers and as most of you know, suck donkey *****!!!! So the topic of my paper is the why can't 4 cylinder DOHC Engines be more fuel efficient? So if you would all like to chime in, not so much of your opinions but some hard hitting facts, I'd be happy to listen and for future reference thanks!!!!

 

More fuel efficient compared with what?

Good place to start: Honda's VTEC-E engines (VTEC-E: the other VTEC...) Basically at low load, low RPM only one intake valve opens, which gives a strong tumble/swirl effect and allows for much leaner running. I don't know if they were still selling these if they would fly, since leaner operation = more oxides of nitrogen, which leads to my next paragraph...

Volkswagen's FSI system is basically a direct injection system, but with a neat trick: it's capable of injecting fuel in such a precise way that a "cloud" of stoich mix surrounds the spark plug, which ignites fine and allows for extremely lean running (this is used, of course, at light load/light cruise also). In Europe the acronym stands for Fuel Stratified Injection, but in the states the "s" is for Straight. This is because in the US, our NOx standards are stricter than EU standards, so the system is "just" another direct injection system.

So, there's one angle to look at the problem from: emissions.

Another semi-related issue, though, is why small cars still run on gasoline at all. Diesels have been popular in Europe for years, but in America, whether it be the "dirty oil burner" stigma or the (until recently) too-high sulfur content of the fuel, we haven't gotten very many small diesel hatchbacks. Or, to remove our dependency on foreign oil completely, why not electricity? GM's EV1 was doing well, despite an internally sabotaged marketing campaign. GM decided sometime around when Texaco got a bigger say in the company that GM should not renew any EV1 leases (the only way to get one) nor allow the owners to purchase the cars back. Today we're told the EV1 didn't succeed because of being a "flop" and "lack of consumer confidence". There isn't a BS flag emoticon big enough to post next to that load of ****.

Just for kicks (and because it might explain better than I can) you should watch "Who Killed the Electric Car?". It might give you a better perspective about the situation as a whole, too.

 

Well, im an engineer, so I dont do the whole writing thing haha. as for fuel efficient 4 cylinders, the advent of direct injection has really helped, but beyond that its hard to improve... the thermal efficenty just isent that great.

looks like koto is going to handle this well. haha.

 

Are we talking about diesel, gasoline, LPG fueled engines?

If it doesn't matter, it might help on your paper to discuss all the major fuels and their effects on efficiency and future viability.

Tony

 

Contrary to what koto might think, I got an A in English Comp. II. Highest in my class actually.

It's not that the DOHC I4 can't be more efficient. I wrote a similar paper in English on gas mileage, and it's more about engine size than engine efficiency.

IE-It takes 33 horsepower (arbitrary number pulled out of my ***) to propel a mid size passenger vehicle 60mph with all but the A/C on. Yet the vehicle comes with a 185hp engine. Had it been given a 60hp engine, the vehicle would get better gas mileage.

I'd write a paper specific to engines as it relates to gas mileage, not efficiency directly. (IE-not talking about cylinder swirl, lean burn, V-tak-j-de-m, etc) If it interest the reader (the teacher, or audience if it's a speech*), they are more likely to listen to what you say rather than how you say it. IE-teacher might miss a wordy sentence if she was kinda interested in what you're saying rather than solely looking for errors.


* I took Public speaking and got a 104 in the class and one of my speeches was on engine design and efficiency, and another on engine selection as it relates to gas mileage. The later had the entire class and the teacher's full attention.

 

I have no beef with you Pat. Your English is fine most of the time. Speaking of which...

fixed.

 

I would love to read that presentation! lol and mang doo I suk att Engleish!!! It's not my favorite class I'll tell ya that!!! so I'm glad to see this enthusiasm from every one thanks!!!!!

 

Lets just use our standard 1.6L miata engine as reference.

So Gasoline

 

Hehe, I vaguely remember it actually. I don't have the speach with me though.

Also, most engineer's don't like eangish, but it's important **** actually. That's why koto keeps me in line.

 

well that sucks i could've used that lol....w/e old fashioned way here i come

 

Not to crap on this thread, But I wanted to watch that, but I hate having to keep switching to different videos so I did alittle searching...

Google video, 1:32:27

Who_Killed_The_Electric_Car_Vostfr.mp4

 

You have to suck donkey ***** as part of an English class?

Freaky.

 

I got a doctor's note to skip that day.

Study the CVCC engine design that Honda designed way back when. It almost had two combustion chambers. It was great for mileage but also wouldn't pass emissions as the rules tightened up. Are you seeing the pattern developing here? The EPA and the environmentalist lobby are a big part of the problem. You've seen guys here on the forum that are able to pick up huge gains in cruising fuel economy by adjusting their fuel ratios to levels that are less than perfect for emissions.

Safety equipment has made the cars much heavier than before thereby exacerbating the problem, but that's not on your topic.

Turbos are the way of the future according to the automotive press I have been reading lately. They can acheive great highway economy for the cafe standards with a small engine, and still yield the power to accelerate briskly enough to satisfy consumers through the use of turbos. The press is talking about the next generation of Mustang GTs and Camaros having direct injection turbo v6s instead of v8s as the top engine option. Go figure...

 

Wow koto; I guess I should be even more careful with my English!

 

Fixed

 

If you want some good info on engine efficiency, just google "OTTO CYCLE - EFFICIENCY" You will find some good information for your research paper, just make sure to cite everything properly. Very small improvements have been made in internal combustion engines in the last 100 years. I think they are around 30-35% efficient? Turbo's actually improve efficiency.

Anyways, I did my research paper on MIG vs. TIG welding for beginners. It was awesome because I used it as an excuse to weld my exhaust on my car. Free school materials in the name of research ftw.

 

Thanks!

 

Hell yeah, get er dun! When I was in HS I rebuilt a set of heads for my 302, used the automotive shop's 5 angle carbide seat cutters, built parts for my car, all kinds of projects. Got grades for them + free materials and access to every tool imaginable = win.

 

lol wtf lol

 

You said it, man.