Physics 29 Efficiency Of Heat Engines (14 of 14) The Otto Cycle

[@erfanagheli1644]

You are the best. Three years of physics, I could not pass without you. (Mechanic, Electromagnetism, and Thermodynamic). I only watched your videos like I am your student, and took the test in my class. Thank you for always being there and answering my questions. I got an 'A' in all my physics classes.

[@MichelvanBiezen]

GREAT JOB! That took a lot of hard work and dedication

[@MichelvanBiezen]

If the example in your work book doesn't include the "n" which stands for "number of moles in the gas sample", then it probably means that they are assuming one mole and therefore they omit that variable. It is better to include it and state that it is "one".

[@thiha8372]

I've been sitting with one question for 2 days for not knowing that the mole is 1 if it is not specified. Thank you so much for your advice!

[@edwardburroughs1489]

LOL Otto-mobiles, good one!

[@miguevilla1026]

Your intention to explain was the best but unfortunately not seen on the board what explains. Thank you👍👍👍

[@Evan2301]

The word "automobile" is an hybrid word coming from latin "mobile" which is "motion" and from Greek "auto" which is "oneself" or "itself". It has nothing to do with Otto which is just a coincidence that its name is pronounced in the same way as Auto.

[@MichelvanBiezen]

Benjamin Henx Great explanation. Thanks

[@njeridiva85]

You sir are AWESOME. Cheers to greatly contributing to my Engineering degree!!!

[@MichelvanBiezen]

A carnot cycle is different There is a video on the carnot cycle

[@jasminemirkovic620]

oml can anyone appreciate this man for clear explanation instead of shitting about otto and auto.. -_-

[@simplythinking-abc]

I just can't explain how much this video has helped me!

[@morrocantocador]

whether its Ottomobile or automobile you are presenting a good stuff on your channel. keep going. By the way looking to your family name are you from German, Netherlands or Belgium? i'm just curious about your origin because we see this name so often here "Van+..."

[@MichelvanBiezen]

Good insight. Yes indeed I grew up in Belgium. Thanks for the comment.

[@MichelvanBiezen]

Thank you for that insight.

[@foxhound1008]

Really enjoy your videos. Wouldn’t this be an alternative method to figure out the efficiency: The area under the curve from C to D is the work done by the gas (Expansion) The area under the curve from A to B is the work done on the gas (compression). If I subtract the area from AB from CD, this should be the net work done by the engine (energy extracted). This should be equal to the change in internal energy, as indicated by the temperature change, from C to D. Would not this be reflected by Qh-Qc/Qh?

[@MichelvanBiezen]

The area inside a complete cycle (when the direction is clockwise) is equal to the work done by the gas.

[@ironuranium3927]

check at 8:24 there will be (+t(a))

[@emmanuelmonforte9928]

Bottom line High gamma, high compression ratio = higher efficiency High gamma, Low compression ratio = high efficiency Low gamma, high compression ratio = low efficiency Low gamma, low compression ratio = lower efficiency Right sir?

[@Aapton]

great video, although it's automobile, not ottomobile, as everybody knows, but I was not sure whether the lecturer was serious or joking :)

[@MichelvanBiezen]

Yes, you are not the first one commenting on the otto vs auto.

[@jamirahamed6023]

I watch your lecture. It is awesome. Thanks lot

[@historyisthebest5831]

Sir. In my textbook, there's a statement describing that there must be heat transfer out of the system(Qc) in order to get a net work output. The heat transfer process is d to a in this video which is an isochoric process. I don't understand why heat must transfer out to get a net work output. Isn't work in an isochoric process 0? The situation in my book is exactly an otto cycle like the one in your video/

[@MichelvanBiezen]

For a thermodynamic cycle to perform work, it must take in energy (Q) from the environment since in a cyclic process, the internal energy of the gas returns to its original amount after each cycle.

[@tirannnus]

The net work done could be calculated two ways: Using the Cv*(dT) method or Integrating PdV where P = C/V^k Right?

[@sirinafl]

Am I only one who notice that; He made 2 mistakes consecutively and mistakes canceled each other.

[@numbo655]

What were the mistakes?

[@antiquarian1773]

magic

[@stevedasilvaferreira6098]

Included minus, in efficiency equation. Supposed to be plus. +1 identified

[@gooddeedsleadto7499]

Could u do entropy change problems with examples for various cycles like Otto, Diesel, Dual, Atkinson and compare it with Carnot Cycle? Thanks

[@MichelvanBiezen]

Good suggestion. Not sure when we can make them. We are working on other topics at the moment.

[@shylildude]

at 8:25 on the last term of the numerator, shouldn't that be +Ta? also, does this apply to diesel engines?

[@MichelvanBiezen]

shylildude Good catch. Yes, that should have been a +Ta. Actually I forgot to place the parenthesis around them -Td+Ta = -(Td-Ta)

[@stephendee7839]

Michel van Biezen Add a comment to the video at the point of the error. I noticed this, too.

[@radimollov4562]

what does the formula T1V1^gama-1 = T2V2^ gama-1 represent?

[@MichelvanBiezen]

It represents the relationship between the state of a gas defined by its temperature and volume at one point to the state of the gas defined by its temperature and volume at a second point after it has gone through an adiabatic expansion or contraction.

[@kiddyflo]

Good video man. Helped me on a sticking point. But just a not on the word "auto-mobile". The auto-mobile is called auto-mobile from Latin. Auto- meaning self and -mobile meaning moving/movable. Hence auto-mobile means "self moving"

[@sshah5893]

I am working through my workbook as well as following your example. I'm confused since the example I am looking through there is no "n" value.

[@nishantboddupalli]

"automobile" originates from "automatic" and "mobile", not "Otto" as he says at 0:30

[@MichelvanBiezen]

correct

[@scoobysharky]

sooooo... it was a troll?

[@agriculturalengineeringwit6808]

Good explaination

[@Mech.Masters]

I have a good doubt,think on it........4-1 process represent exhaust and it takes place at constant volume....Now link this thing to movement of piston.Exhaust takes place when the piston moves from BDC to TDC this means volume is changing during exhaust........still why does the cycle shows a constant volume exhaust.

[@MichelvanBiezen]

The volume is constant from b to c and from d to a.

[@Mech.Masters]

I got the answer..

[@edwinthomas544]

SIR YOUR EXPLANATIONS ARE FAB BUT COULD U JUST SOLVE SOME MORE COMPLEX PROBLEMS LIKE THE PROBLEMS HAVING 2 REVERSIBLE ENGINES .IF U COULD IT WOULD BE A GREAT HELP. THANK YOU FOR U SERVICE

[@MichelvanBiezen]

We just started a second series of thermodynamics which will be covering more advanced topics. (But it will be a while before it is completed).

[@smailwaltit38]

thanks for the great video !

[@subhanshu88]

thnku for dis great video

[@heavy2028]

great videos thanks!

[@dimitardimitrov9958]

Why "Ta" is become "- " in 8,25min. of the video ? It was "+"before that....

[@MichelvanBiezen]

Dimitar Dimitrov Good catch. Yes, it should be a (+) I corrected it on the next step.

[@dimitardimitrov9958]

Thank you, I really enjoy your way of teaching,...compliments!

[@AnuragPradhan101]

is it carnot cycle ?

[@Nanba91]

THANK YOU

[@latifabechri8951]

Thank youuuuuu

[@LuisVasDeCamoes]

its automobile (automatic + mobile)

[@787310]

why are these videos so blurry

[@MichelvanBiezen]

+Richard Gluten These are the videos we produced in our first year and we were learning the tricks of the trade. You can improve the clarity by clicking on the "settings" button and click on higher resolution.

[@lucasleal2915]

what is C sub v?? can anyone help?

[@MichelvanBiezen]

c for an object is its specific heat (the amount of heat you need to add to raise 1 g of the object by 1 degree centigrade c for a gas is the amount of heat you have to add to raise 1 mol of the gas by 1 degree centigrade. But for a gas there are two values for c, one for when the volume stays constant and 1 for when the pressure stays constant. Cv is the specific heat at constant volume.

[@lucasleal2915]

Ahh okay I understand, thank you for the speedy response it really helps now that my exams are coming up!

[@MariaM-he6ng]

Definitely NOT named after Otto! AYTO is a greek word still used in modern Greek and means IT, ITSELF.

[@MichelvanBiezen]

Yes, I have been reminded by a number of viewers......

[@AutoMania46]

supalike.... cheers...

[@ryanibrahim5464]

This video is as blurry as my idea on what I want to do with my life

[@MichelvanBiezen]

It is indeed. One of earlier videos before we knew what we were doing

[@Philwahl805]

False information after only 30 seconds? How can I trust the rest of the lecture now?