Weight is only relevant to acceleration (which is partially recovered), hills (partially recovered), and rolling resistance which is only ~5% of energy usage. Even with a consistent load on the highway the batteries can help by removing parasitic loads on the engine like alternators, a/c compressors, and power steering pumps. Depending on torque demand and specifics of the engine/transmission, thrashing the battery could also be more efficient than ICE alone.
I'm sure there's stuff I've missed, but I think those are the main reasons why a number of hybrids have highway EPA ratings 10-15 mpg higher than the highest MPG ICE car ever produced.
you're totally right, I mixed up my facts. they are 10-15 mpg higher than the highest MPG ice car currently produced for the US market which is the Mitsubishi mirage.
Not quite. Diesel engines are most efficient (~40%) at full throttle, low-mid revs, and drop to <30% at low throttle. With some battery trashing you could see the engine work at some 20-50% duty cycle on the highway.
Not quite. otto cycle is most efficient at full throttle due to throttle valve pump losses.
Diesels are most thermodynamically efficient at low throttle because it takes time to combust the fuel. During this time the piston expands and the compression ratio drops.
You can see the derivation and formulas in Faires (and older edition. Even the 70s edition lacked the chapter). Actually just comparing the the PV diagram of otto and diesel makes it obvious.
First a nitpick that is unfortunately important - diesels' don't have a throttle; what we call throttle is the fuel cutoff ratio, or how long we inject fuel for.
This is important because what distinguishes Otto and Diesel cycles is not the fuel, but the form of ignition. Otto cycle analysis is assumed instant, whereas diesel cannot be assumed instant. Car otto engines are fast enough that a diesel-like cycle is used for advanced analysis.
Low rpm and low throttle improve diesel's efficiency for the same reason - the injected fuel has more time to burn without the piston expanding.
As [1] points out in page 180:
"Study of equation (62) shows that as r e increases, the bracketed factor increases, and the efficiency decreases (Fig 99) Therefore, the lower fuel cutoff ratios are conducive to higher efficiencies but larger ratios result m greater power "
Also, very interesting, Diesel's efficiency is lower than Otto all else being equal. However, due to knocking, gasoline (octane ~ 90) engines have low compression ratios and lower efficiency than Diesels. However an otto methane (octane of 130) engine would kick diesels' butts
Diesels running constant RPM will increase throttle with increasing load to keep their RPM. That's a matter of injecting more fuel. It's how every diesel based generator works.
As for high octane kicking diesel's butts: yes, but that fuel is far more expensive so it tends to be diesel that wins that particular contest in the economy department.
I went to one in LA, extended family went for Xmas.
It's weird, super produced. The back wall was a teleprompter and a timer, so they could time this service and start the next.
I don't go to any church, so this was extra over the top.
I once, after four years of acting as sole line of defense against a destructively stupid but politically influential "colleague," I gave warnings then gave notice.
I ended up jumping to another department where I watched him bring in an expensive vendor to implement a replacement for a system I had been using, and then watched corrupt files start appearing in the production files. I was there just long enough to hear about his quiet exit from the company.
Someone else needs to quietly exit from the company if they hope to get this out of the grease fire. At this point, we'll all see what happens pretty quickly I think, but this looks to me like a ship with a thousand leaks and a drunk captain who won't come out of his cabin because people yell at him about problems that are not his when he does.
In 10 years as a "professional" I've never heard it until the last 6 months.
I'm EE so different circles, but closer to pure SW people in those last 6 months.
Likely because it’s from an old book that few in the gen xyz have read. It’s been transformed to mean ‘understand’ and it’s pretentious to use in regular settings.
I’m a fan of the movie Kin-dza-dza it doesn’t make it acceptable for me to walk around saying ‘Ku’ to strangers.
And if you do read that old book it has a lot of overt sexism and to me it felt like some sort of incel fantasy (I really enjoy older scifi so understand times were different back then but Stranger in a Strange Land felt over the top). So now I associate that word with all the problematic aspects of the book and assume the person using it is either using the word without having read the book or didn't see a problem with the book when they did read it. Neither really makes me think highly of the person.
The book was progressive for its time, shocking to publishers for openly discussing sexuality, religion, establishment.
People reading it 60 years later and finding it sexist I think are projecting a bit of their own insecurities. Considering the book, the current dominant religious institutions on the planet, the scriptures behind those beliefs and institutions, and what’s been going on in America over the past 4 years as far as women’s rights.
>So now I associate that word with all the problematic aspects of the book and assume the person using it is either using the word without having read the book or didn't see a problem with the book when they did read it. Neither really makes me think highly of the person.
You cannot separate the book and person reading the book. Its ok to disagree, its ok to have different views.
Where are you getting the idea I can't separate the book from the person reading it? I've personally read the book. I have no problem with people reading it or even enjoying it.
My comment was on people who are regularly referencing the book by using the word "grok". When you do that, you are intentionally associating yourself with the book and implying other people should read the book if they don't want to feel left out.
I think it would be like a youngish person today walking around using 1980s slang. It seems pretty clear in use that it is a conscious, affected choice.
Where do you sit in the organization? How do you "get ahead of projects"?
Im a Systems Engineer by title, but have no idea where my place is (its all confusing). I'm basically an 'super IC' on a team - and try to play with other groups my group interacts with... So there is no power to set the design. Basically just answer 'will this work with your part of the system'?
I basically end up just finding issues, POC end-to-end (well outside of my discipline: I'm a HW guy to I'll do a FW to Cloud security thing).. and well, why business does the HW Systems person have suggesting we use PKI for authentication?
