111–120 of 172 posts
This is a great illustration that demonstrates why gasoline engines NEED to die and be replaced by better, more efficient engines.
"Engines get hot - the cooling system of a car going down the freeway dissipates enough heat to keep two average-sized homes warm!"
Think about that for a while. ICE's just have a thermal efficiency of about 30%, the rest becomes heat.
Love 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.
I also remember seeing a few Mazda rotary pickups in my early years in the US - very cool but apparently not very reliable and very inefficient.
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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…
We even have a Ministry of Medical Magic in the US now: http://nccam.nih.gov
You know what they call alternative medicine that works?
Medicine.
(cf: Tim Minchin, 'Storm' http://www.youtube.com/watch?v=HhGuXCuDb1U)
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This will only work if your engine can achieve high enough compression to take advantage of the higher octane number. Many engines can't.
But if the engine is running on lower power because of the knock sensor, higher octane should be called for, right?
Love 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.
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But if the engine is running on lower power because of the knock sensor, higher octane should be called for, right?
Yes, because that means the knock sensor is reducing compression because it senses lower octane gasoline.
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The new Corvette does something interesting - there's a sensor on the manual gear shift lever that predicts what gear you're going to select, and will do the rev matching for you. Result is a perfect downshift, every time.
Yep, Nissan's 370Z has had SynchroRevMatch as part of its Sport/NISMO packages for a few years now, and from what I've heard through friends it's very simple and works really well... Although it makes me wonder at what point on the spectrum does a "manual" become an "automatic" http://en.wikipedia.org/wiki/Synchronized_down_shift_rev-mat...
I'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.
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AFAIK, the Chevrolet Volt (and Opel clone, etc) is the only one where the engine just charges the batteries, and the drive wheels are run by the electric motor alone. From a technical standpoint, it's a good design for a hybrid - you can optimize each part of the system separately. But GM didn't quite get the car as a whole correct -- it has some ergonomic problems, priced higher than the value (perceived and actual)…
^ - this. Volt fires up gas motor to optimum efficiency point to serve as a generator for the electric motor, which is the only motor connected to the drivetrain
This is a common misconception. The Volt will drive the wheels directly from the gasoline engine when driving at high speed (>70 mph).
http://blogs.cars.com/kickingtires/2010/10/the-great-chevy-v...
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That isn't true, most hybrids still have a mechanical connection between the combustion engine and the drive wheels. That is, the Prius, Ford hybrids, GM hybrids, I'm sure others.
Agree, Prius and others aren't actually efficient in terms of fuel usage. And they aren't "green".