I have this thermodynamics question.

Keep in mind I could honestly not care less about engines. It's not exactly pertinent toward my major.

I calculated the kW an engine produces per cycle. The engine is running at 1600 RPM. I converted that to RPS, and multiplied that by the number of cylinders.

W (total) = W (per cycle) * RPS * cylinders

This doesn't get me close to the answer. It's about one fourth. This is a four stroke engine. Wouldn't a 4 stroke engine only make power once every two revolutions?

Or am I thinking backwards?

 

yup

intake, compression, POWER, exhaust

 

Correct...it will make power once per cycle, and per two crankshaft revolutions. Make sure your units work out to the unit of W or kW after your calculation.

 

It's off by 20 kW compared with the book answer. That may be the choice in specific heats, though.

 

Yeah, all the engine stuff I did wasn't straight power...had to do with temps, pressures, pressure ratios, etc. Post the numbers you have for the problem, or the problem itself?

 

BTW, if you want the units to work out correctly to make the answer come out to kW, the W (per cycle) needs to be in kJ (work and not power), and multiplied by the cycles per second. So figure out the work per cycle, instead of power per cycle.

 

I'll post the actual problem in a few. I need to take more advil. My head is busted.

 

Thermo cramming crew checking in. This shit is gay.

 

according to gran turismo 4, an oil change can recover about 50hp on a R33 skyline.

 

Only if you use Royal Purple :crazyr: