Why is fuel consumption higher at low RPM?

[mandala09]

Why are usually more wasteful fuel engine at low RPM, as the example image below, 900 RPM more wasteful fuel consumption than 1600 RPM.

 

[wahyudi.jr]

Why are usually more wasteful fuel engine at low RPM, as the example image below, 1600 RPM more wasteful fuel consumption than 900 RPM.

Mr Mandala, if I may be corrected, the data shown in the picture upside down with your statement. fuel consumption at 900 rpm is higher than at 1600 rpm. why is that? What kind of analysis?

 

[mandala09]

Mr Mandala, if I may be corrected, the data shown in the picture upside down with your statement. fuel consumption at 900 rpm is higher than at 1600 rpm. why is that? What kind of analysis?

Excuse me sir, I was wrong to write and I have to change it. Can you help me to analyze it?

 

[mender]

Part of the issue will be the longer time that heat can be lost to the cylinder walls, reducing the amount of energy to expand the air and be converted to mechanical energy.

 

[mandala09]

Part of the issue will be the longer time that heat can be lost to the cylinder walls, reducing the amount of energy to expand the air and be converted to mechanical energy.

Although the engine was already in the working temperature if the heat will still be lost in the cylinder wall ?

 

[jim hardy]

this thread has some relevant information in it.

https://www.physicsforums.com/showthread.php?t=244434

 

[mandala09]

this thread has some relevant information in it.

https://www.physicsforums.com/showthread.php?t=244434

Thank you so much Jim hardy. I get a lot of good explanations of the link that you gave.

 

[jim hardy]

here's a reasonably short introduction that'll help you with terminology.

http://www.epi-eng.com/piston_engine_technology/engine_technology_contents.htm

 

[mender]

this thread has some relevant information in it.

https://www.physicsforums.com/showthread.php?t=244434

Curious that the thread was locked; I didn't see anything worth locking it.