Water boil at exactly 100 degrees Celsius... not the conversion of 212 degrees Fahrenheit. Americans. ;-) Nice job still.
> Water boil at exactly 100 degrees Celsius
Few people live exactly under 1 atm for any length of time.
How a Car Engine Works
91–100 of 172 posts
Re: How a Car Engine Works
#92I'm going to suggest that if you want to call yourself an engineer in any field, you should be able to quickly understand, among other things, how engines and air conditioning work. If not, there's always the management track ;) Good to see there are some other gearheads here.
A professor in college once told me that if you can't explain a technology, you might as well assume it's magic.
Isn't that how medicine works?
Re: How a Car Engine Works
#9393 octane is premium fuel in the US? Petrol in the UK starts at 95 and premium is 98. What’s the practical difference then?
Octane is the US is the average of MON and RON as stated in the other reply, which usually places it about 5 point below the RON number which is used in Europe and many other places. Also, in higher altitudes you don't need as high an octane, so where I live (4000ft-9000ft) premium is 91.
Re: How a Car Engine Works
#94Earlier quoted context omitted.
That's one of the major reasons the GT-R is so quick off the line and down the quarter mile. It was the first production car with a dual-clutch transmission that was actually realistically priced, and it's still arguably the most cost-effective.
Actually VW sold a dual clutch DSG transmission in the 2003 R32, years before the GTR hit the market, and for a fraction of the price. All other things the same, a dual clutch is not much faster than a properly-operated manually-clutched gearbox, but in the case of the GTR, we'll never be able to make that comparison.
> a dual clutch is not much faster than a properly-operated manually-clutched gearbox
That's not correct. When the GT-R first came out I read a great article about why it was so damn quick down the 1/4 compared to super cars that are 2-6x more expensive. The reasons were:
1. Most of them dyno at around 480hp AT THE WHEELS. So it's making more power than Nissan claims.
2. It's the first car to get all the electronics (stability control, etc. etc.) good enough to actually make it faster, not just get in the way
3. The dual-clutch gearbox changes were so fast, they did a comparison of how long the GT-R is in neutral during the 1/4 compared to other supercars with regular manual gearboxes. I remember the time difference being in the .4-.8 second range. That was the #1 reason it was so fast - it spends an extra 0.5 seconds actually putting power to the road, which is obviously huge in a ~12 sec 1/4.
Re: How a Car Engine Works
#95Omg I can't believe they omitted the V-4! This is a fun video about ignition order: http://youtu.be/MwEbwKBic6w (though it's more complicated since there are both 180 and 360 degree-firing V4s).
It also left out the inline-6 (different from the flat-6) and the wankel. Here's a couple more piston configurations:
http://en.wikipedia.org/wiki/Category:Piston_engine_configur...
http://www.caranddriver.com/features/the-physics-of-engine-c...
Another fun subject is harmonic vibration and balance. Certain configurations require things like balance shafts and harmonic balancers (arguably unnecessary fluff) to offset the intense vibration, and modifying your engine can result in it self-destructing if this isn't taken into account. Inline and flat 6's and 12's are the best balanced, though the inline is more efficient and requires less maintenance than the flat.
http://en.wikipedia.org/wiki/V6_engine#Balance_and_smoothnes...
Re: How a Car Engine Works
#96You guys are unreal with your comments - is it jealousy or something. Whatever it is it make me want to never come here again
I don't know what you're talking about, most comments look very positive to me.
Re: How a Car Engine Works
#97Earlier quoted context omitted.
A professor in college once told me that if you can't explain a technology, you might as well assume it's magic.
Isn't that how medicine works?
I agree. When I first started looking into medications like Aderall, it was surprising to find how little we actually know about how medicine works.
Take the above example - we really don't know how it works. We measure the amount of dopamine/serotonin in the spine before and after you take it so we assume it increases the presence of those chemicals in the brain, but it's not really mapped out.
A lot of people have the misconception that we understand the body the way we understand other technologies. That you can balance a chemical equation and deduce how something will effect the body.
While we understand a lot, this really isn't the case. And for all practical purposes it sometimes is treated like "magic".
Re: How a Car Engine Works
#98Love it, best thing on HN today! Could you add diesel and 2 stroke?
Don't forget the Wankel (rotary) engine! Few people have even heard of them, and even fewer have any idea what they are or how they work. I love my dorito on a stick.
Re: How a Car Engine Works
#99I'm going to suggest that if you want to call yourself an engineer in any field, you should be able to quickly understand, among other things, how engines and air conditioning work. If not, there's always the management track ;) Good to see there are some other gearheads here.
A professor in college once told me that if you can't explain a technology, you might as well assume it's magic.
Cue the Arthur C. Clark quote:
“Any sufficiently advanced technology is indistinguishable
from magic.”Re: How a Car Engine Works
#100Earlier quoted context omitted.
Actually VW sold a dual clutch DSG transmission in the 2003 R32, years before the GTR hit the market, and for a fraction of the price. All other things the same, a dual clutch is not much faster than a properly-operated manually-clutched gearbox, but in the case of the GTR, we'll never be able to make that comparison.
> a dual clutch is not much faster than a properly-operated manually-clutched gearbox That's not correct. When the GT-R first came out I read a great article about why it was so damn quick down the 1/4 compared to super cars that are 2-6x more expensive. The reasons were: 1. Most of them dyno at around 480hp AT THE WHEELS. So it's making more power than Nissan claims. 2. It's the first car to get all the electronics…
You seem to have ignored my "All other things the same" qualifier - that means you have to assume that power, weight (except for the difference between the gearboxes,) suspension, environment, tires, and everything else, is identical for the quoted part of my sentence to apply.
I don't see how your first two points are relevant to what I said, or your original post. You can love the GTR all you want, I don't mind, and I never claimed that there was anything wrong with it.
As for point 3, if you were to compare to a theoretical manual transmission GTR, that half a second of extra power would still only net you a couple tenths advantage, since acceleration and aerodynamic drag are nonlinear.
And I stand by my claim that a couple tenths on a 12 second quarter mile is 'not much faster.'